hmmmm.................

B and C are neck-to-neck.

In the stem we have

Lofgren's disease has been observed frequently in commercially raised cattle but very rarely in chickens. Both cattle and chickens raised for meat are often fed the type of feed that transmits the virus that causes the disease. Animals infected with the virus take more than a year to develop symptoms of Lofgren's disease, however, and chickens commercially raised for meat, unlike cattle, are generally brought to market during their first year of life.

"Immunity" meaning is having resistance to a disease.
As the stem says though it is very rare to find the disease in the chicken it shouldnt be thought as "immunity" 'cos the chicken generally are taken during their first year of life. Though "immunity" has not been given it is the ability to not see the disease here I thought

Hi Guys,

While we are discussing the option B and C, let's revisit the question once again...the question says:

Which of the following is most strongly supported by the information provided?
...
B: There is no way to determine whether a chicken is infected with the Lofgren's disease virus before the chicken shows symptoms of the disease.
C: A failure to observe Lofgren's disease in commercial chicken populations is not good evidence that chickens are immune to the virus that causes this disease.
...
Now if we consider option C, what it signifies is that the:
conclusion of the given argument, say Y, is: Chickens are immune to the virus that causes this disease.
and it's given evidence in the argument, say X, is: A failure to observe Lofgren's disease in commercial chicken populations
And the option C then means that X does not lead to Y.

So, for option C to be true, author must provide both coclusion - Y and evidence X in argument, whereas,
- the argument never talks about the conclusion to be Y (it can be infered only), and,
- Also you cannot consider X as an evidence (not even as an assumption) because author did say that disease can be observed rarely in chicken...the author never talked about failure to observe disease.
So, even if Y is considered as inference (as trivikram pointed out), the option C cannot be considered as true, since X is never mentioned as evidence or assumption.

Using POE, the option B then wins.

Let me know if you have some other views.

Argument (for easy reference): "Lofgren's disease has been observed frequently in commercially raised cattle but very rarely in chickens. Both cattle and chickens raised for meat are often fed the type of feed that transmits the virus that causes the disease. Animals infected with the virus take more than a year to develop symptoms of Lofgren's disease, however, and chickens commercially raised for meat, unlike cattle, are generally brought to market during their first year of life.
"

It's clearly B!

"however, and chickens commercially raised for meat, unlike cattle, are generally brought to market during their first year of life." ---> if there's a way, besides symptoms, to determine whether a chicken is infected, the chicken won't be brought to sell in the market! ---> It's what B clearly say.

I will go for C.

Here is my explanation:

Premise1: Lofgren's is rare in chickens than it is in cattle.
Premise2: Both cattle and chicken eat same food that may cause disease.
Premise3: It takes one year for symptoms to appear.
Premise4: Chickens are brought to market in their first year.

Now the question asks for inference NOT the conslusion.
What we can infer?

1. It takes 1 year for symptoms to year doesn't mean that the disease can not be detected in first year. Only thing we can infer is NO sysmtoms can appear before 1 year and if sysmtoms are there then the chicken is atleast one year old.

2. The rarity of disease is not related to food. There MUST be some other cause of rarity.

3. No symptoms of disease have been observed in chickens brought in market.

Using 2nd inference we can say that if we have not observed the disease in chickens then it doesn't mean that they are immune. Chickens are also susecptible to disease but only thing is we have not observed.
_________________

SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008

Used the exact same line of reasoning. NO WAY = 100% Far too extreme.

(C)

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