Retroviral injections prove to be the only effective means of treating

Bunuel, would be happy if you provide an explanation to this answer, i gave answer as D, though B is correct, I am unable to understand the explanation, it tells that
"Nevertheless, it cannot be stated that retroviral injections are always beneficial for human health, since they are known to reduce immune system activity in some cases, and persons with reduced immune system activity are likely to be afflicted by various infectious diseases."
How can some be referred to "Treatment of some serious diseases always results in reduced immune system activity."

Retroviral injections prove to be the only effective means of treating some serious diseases. Nevertheless, it cannot be stated that retroviral injections are always beneficial for human health, since they are known to reduce immune system activity in some cases, and persons with reduced immune system activity are likely to be afflicted by various infectious diseases.

Which of the following statements can be properly inferred from the passage above?

(A) Retroviral injections are the major cause of reduced immune system activity.
(B) Treatment of some serious diseases always results in reduced immune system activity.
(C) Retroviral injections are not beneficial for human health.
(D) People who contract serious diseases will be afflicted by various infectious diseases.
(E) Retroviral injections are the only effective means of treating some infec-tious diseases.

Hello!

Option A says that Retroviral Injections are the major cause of reduced immune system activity, which is not true. There can be various other reasons for the same.
In Option C, it is not accurate to conclude as retroviral injections are not beneficial for human health.
Option D is not compulsory, as the ones who have a low immune system can be affected but not all, so it does not help us.
Option E is irrelevant

So, we can eliminate Options A, C, D and E

Coming over to Option B,
It helps to establish the fact that; Treatment of some serious diseases always results in reduced immune system activity because every person suffering from a serious disease should have experienced a low immune off late.

Option B is better than any of the other options.

Official Answer-: Option B

Let me know if any point is unclear.

Thank you!

Regards,
Raunak Damle!

My approach to CR:

Start with the question stem. Here the question stem indicates that the task in hand is to 'infer'.

Summarise the argument:
RVI "only" effective way to treat some serious diseases.
RVI "not always" beneficial to human health. This leads to reduced immune system activity (ISA) thereby contracting an infectious disease.

Since the question does not refer to any specific text or any specific part to be inferred, let's look at the options for some help. (Skipping Pre-thinking)

(A) Retroviral injections are the major cause of reduced immune system activity.
RVI reduces ISA in "some cases". This does not necessarily mean that RVI is the major cause of reduced ISA.


(B) Treatment of some serious diseases always results in reduced immune system activity.
RVI is only effective in some serious diseases.
RVI leads to reduced ISA in some cases.

It can be inferred that 'some serious diseases' and 'some cases' overlap. And inferring this will also retain the argument logic intact.

(C) Retroviral injections are not beneficial for human health.
RVI is 'not always' beneficial for human health. It means that sometimes RVI can be beneficial. However, the option is a complete 180 deg.


(D) People who contract serious diseases will be afflicted by various infectious diseases.
Only those with reduced immunity will be afflicted by infectious diseases not everyone. So this cannot be inferred.


(E) Retroviral injections are the only effective means of treating some infectious diseases.
RVIs are only effective in treatment of 'some serious diseases' which can be 'infectious' or 'non-infectious' and this distinction is not discussed in the stimulus.


Here the larger challenged I faced was to decide between options B and D but if one pays close attention to verbs such as 'will', 'likely', 'only' (determinative/probabilistic verbs), he/she will be able to figure out the correct option.


Hit Kudos if you like the explanation.

BenCrackVerbal

1. Would be great if you can post a detailed solution. I am sure all of us who marked E are missing some critical point
2. Also, any specific reason for the dash within the word infectious in E? Or is it just a typo?

(A) Retroviral injections are the major cause of reduced immune system activity
The passage does not provide information on the different causes that reduce immune system activity and their relative impact and hence we cannot be sure if these injections are the major cause
(C) Retroviral injections are not beneficial for human health.
This option goes against the first line in the passage says that 'prove to be the only effective means of treating some serious diseases' and hence can be eliminated
(D) People who contract serious diseases will be afflicted by various infectious diseases.
Not always, because the immune system activity drops only in certain cases

(B) Treatment of some serious diseases always results in reduced immune system activity.
(E) Retroviral injections are the only effective means of treating some infec-tious diseases.

The first line states that 'Retroviral injections prove to be the only effective means of treating some serious diseases' Now this line mentions some serious diseases and not some infectious diseases, hence we cannot be sure that E can be surely inferred from the passage

In case of B, 'they are known to reduce immune system activity in some cases'. If they reduce only in some cases then how can we conclude that they reduce in all cases?

This is an inference question. So the answer we choose shouldn't negate any of the statements made by the author...as we are basically going to sum up his statements.
A says retroviral injections are the 'cause'...the author doesn't say so
B 'Retroviral injections...the only means'...only is the keyword here...if this is the only way to treat and the next statement says that these injections are known to reduce the immune system in some cases, it obviously follows that this treatment being the only treatment, when used, will result in reduced immune system...Hence correct
C is wrong as the first sentence clearly says it is the only means of treatment...so certainly benefecial
D is completely out of scope of this argument
E says retroviral injections are the only effective means to treat some infectious diseases whereas the argument says 'to trest some serious diseases'..this is a distortion
So combining the first two sentences and the key word'only sffective', B should be the right answer

Posted from my mobile device

None of the choices are correct.
When we talk about inference, it "has to be true" based on the evidence in the premise.
Let's go through the choice one by one.

Premise: RV injections are the "only" effective way to treat some infectious diseases, but in "some" cases, they are known to reduce immunity. Further, people with reduced immunity are "likely" to be afflicted by various infectious diseases.

a) From nowhere it can be inferred that RV injections are the major cause of reduced immunity activity. (....but in "some" cases, they are known to reduce immunity) Incorrect
b) We are talking about some serious diseases, it can be the ones which can be treated by RV Injections and which can't. We only know that RV injections reduce immunity in "some" cases. Hence usage of "always" is absloutely incorrect.
c) As discussed above, RV injections cause reduced immunity in "some" cases. What about the rest? Hence this answer choice makes a pretty strong statement and hence incorrect.
d) It implies that people who contract serious diseases (i.e. people may or may not be treated by RV Injections") WILL be afflicted by various infectious diseases. Incorrect. First people need to take RV injections and among those people, there will be "some" cases where the immunity is reduced. Further among these cases, some may be afflicted by infectious diseases.
e) WRONG.

Premise: Retroviral injections prove to be the only effective means of treating some serious diseases.
Premise: Nevertheless, it cannot be stated that retroviral injections are always beneficial for human health, (i.e. NOT always beneficial)
Premise: since they(Retroviral injections) are known to reduce immune system activity in some cases,
Premise: and persons with reduced immune system activity are likely to be afflicted by various infectious diseases.

Which of the following statements can be properly inferred from the passage above?
So the question is basically asking, What MUST BE TRUE..?

(A) Retroviral injections are the major cause of reduced immune system activity.
==> No where mentioned that retroviral injections are major cause. Eliminate this option.

(B) Treatment of some serious diseases always results in reduced immune system activity.
==>Answers that are not extreme are usually correct on MUST BE TRUE questions. Let's keep this.

(C) Retroviral injections are not beneficial for human health.
==> Very first statement in fact says that some diseases can be cure only by retroviral injections and those are beneficial at least in some ways. Eliminate this option.

(D) People who contract serious diseases will be afflicted by various infectious diseases.
==> May be true. May NOT be true. Argument talks about some disease, that can only be cured by retroviral injections. Eliminate this option.

(E) Retroviral injections are the only effective means of treating some infec-tious diseases.
==> ONLY makes it extreme and moreover argument says retroviral injections cure some diseases but not sure if those include infectious diseases. May include, may NOT include. Eliminate this option.


So, we are left with only one option - option 'B'. hoohooo, no need to further drill down/compare... That's our final answer.
This is a high quality question and I hope my explanation makes sense to you.

By the way, I finalized 'B' as my answer but somehow clicked on 'C'. ­

Retroviral injections prove to be the only effective means of treating some serious diseases. Nevertheless, it cannot be stated that retroviral injections are always beneficial for human health, since they are known to reduce immune system activity in some cases, and persons with reduced immune system activity are likely to be afflicted by various infectious diseases.

Which of the following statements can be properly inferred from the passage above?

(A) Retroviral injections are the major cause of reduced immune system activity. (Nowhere mentioned in passage)
(B) Treatment of some serious diseases always results in reduced immune system activity. (The word 'always' seemed too extreme for selection as an answer choice, since the passage says that in some cases RVI (the treatment) reduces immunity, ie why I eliminated this option)
(C) Retroviral injections are not beneficial for human health. (Not always beneficial is not equal to not beneficial, since not beneficial seems to represent all 100% cases)
(D) People who contract serious diseases will be afflicted by various infectious diseases. (This is a stretch. Affliction by various infection diseases was given in context to some cases in which the immunity goes down, but certainly not for all because it includes cases in which individual might not have had side effects at all, and thus not be prone to any of the various infectious diseases)
(E) Retroviral injections are the only effective means of treating some infec-tious diseases. (I found the word 'infectious' bit awkward here as the passage says that RI has proven to be effective for some serious diseases. Now can we say 'serious' is = to 'infectious', in some cases yes, and I thought this much outside common knowledge is permissible to bring in the scope. This is why I selected E as the answer. But I guess I was wrong as per official answer)

I couldn't find any explanations above that cleared my doubt. If someone wishes to clear it, I wholeheartedly welcome it.

Regards
Arjun

B is actually an extreme answer because of the use of the word "always"
­

This is question has flawed answer choices. It's best to ignore such questions and move on.