Astrophysicist: Gamma ray bursts (GRBs)-explosions of powerful

Because this assumption allowed the author to conclude that now with new properties, that is more important, old classifications, "short" and "long" are no more valid.

Gist:
1. We can categorize all GRB's into short GRB's or long GRB's.
2. But what about an unusual long GRB with some other properties(properties other than duration of the explosion) similar to a short GRB? In which category should we place it?
Well, its a long GRB so clearly we can place it in 'long' category. But the author says we cannot do that. Why? Obviously these some other properties also should be taken into consideration while categorizing unusual GRB's. This is the logical gap in the passage.
Hence the Conclusion: The descriptive labels "short" and "long" are no longer useful.



(A)
The topic of discussion is how to categorize the one unusual GRB detected. It does not matter if no other unusual GRBs are detected or not.

This is telling us nothing about the unusual GRB.

In line with the prethinking.

out of scope

Even if nondescriptive labels are used, how will we categorize the unusual GRB. The question still remains.

The conclusion states that the descriptive labels "short" and "long" have outlived their usefulness.

Option C states that certain properties are more important than duration for unusual GRBs.

Isn't this option incomplete to become the answer?

While the descriptive labels in the discussion might have become obsolete for unusual GRBs they still may serve a purpose for an average GRB.

Following Nightblade354 advise to push my CR skills beyond the limits, I'll post an extensive analysis of this question, explaining the initial thoughts on the stimulus and the reasons why I reject four options and choose one as the winner . I beieve this is one of the best ways to improve in CR. Don't just do questions, but try to extract as much as possible from each of them. I think doing blind review help a lot in doing so (more about blind review here: https://gmatclub.com/forum/mod-nightbla ... 95316.html)

Here is the stimulus: Astrophysicist: Gamma ray bursts (GRBs) -explosions of powerful radiation from deep space - have traditionally been classified as either "short'' or "long," terms that reflect the explosion's relative duration. However, an unusual GRB has been sighted. Its duration was long, but in every other respect it had the properties of a short GRB. Clearly, the descriptive labels "short" and "long" have now outlived their usefulness.

1º Premise: GRBs classified as short/long. This defines duration
2º Premises: Unusual GRB spotted. it was a long one but with the characteristics of a short
Conclusion: short-long labels should be over

Initial thoughts: GRBs have been classified as short or long because it is the term that defines how long the GRB is. But wait, why should they be classified by duration. Is it the only difference between the two types? Not only difference, but the most important one perhaps? mmm. I don't know, let's keep reading. mmm ok. I understand now. There are more properties as to which GRBs are defined, but durations seems to be the most important one. They saw a GRB whose duration was long, but all the other properties were short. OK. So I understand that the conclusion is that GRBs should be classified not in terms of duration.

But wait. What if the one spotted was an outlier? What if 99.9% of GRBs should be classified as short-long because this classifications works? An outlier should break down the terminology that GRBs used to have? mmm I don't think so. The option should give me a good reason why this terminology should be over. Maybe they discovered that other properties are more important or that are able to differentiate better the two types of GRBs. This should be enough. Let's read options having this in mind.

(A) No other GRBs with unusual properties have been sighted.

No other unusual GRBs have been sigthed. Ok, fair enough. This sounds good. This argument says that this is an outlier and could indicate that labels are still good. But hey!. We want actually the opposite. We want to steghtne the argument why the labels should be different and not why they should still be the same. So this is Weakness!. Incorrect

(B) The classification of GRBs can sometimes be made on the basis of duration alone.

This option weakens the argument. If the classification should be made on the basis of duration alone, why would the author conclude the opposite? Incorrect

(C) Properties other than duration are more important than duration in the proper classification of the unusual GRB.

I like this one. It says that other properties are more important. If so, definitely, the author is right in saying that the short-long labels are over!. This is definitely more assertive than option A)!. Keep it!

(D) GRBs cannot be classified according to the different types of cosmic events that create them.

This is out of scope. It doesn't address why the short/long labels should be over. Incorrect

(E) Descriptive labels are easily replaced with nondescriptive labels such as "type I'' and "type II."

Non descriptive? But I think we want labels that describe the different GRBs. Option C is much much better

OPTION C

Astrophysicist: Gamma ray bursts (GRBs) -explosions of powerful radiation from deep space - have traditionally been classified as either "short'' or "long," terms that reflect the explosion's relative duration. However, an unusual GRB has been sighted. Its duration was long, but in every other respect it had the properties of a short GRB. Clearly, the descriptive labels "short" and "long" have now outlived their usefulness.

The conclusion of the astrophysicist's argument is most strongly supported if which one of tbe following is assumed?

Pre-thinking:
Lets recap:
Some rays are classified in 2 ways: long and short. L&S refer to the duration
But now we have been presented with a long ray which has features similar to those of the short ray.
We are asked to find an assumption that supports the conclusion and the conclusion is that the current classification is not useful anymore.

An assumption is that in order to examine rays there are also other factors that are as/more useful as/than the duration.


(A) No other GRBs with unusual properties have been sighted.
This weakens the conclusion. Hence incorrect

(B) The classification of GRBs can sometimes be made on the basis of duration alone.
sometimes is a vague term that could mean 1 time, 2 times..... all times. Since this choice does not have a clear impact on the argument it is incorrect

(C) Properties other than duration are more important than duration in the proper classification of the unusual GRB.
In line with pre-thinking. Hence correct

(D) GRBs cannot be classified according to the different types of cosmic events that create them.
Completely out of scope. Hence incorrect

(E) Descriptive labels are easily replaced with nondescriptive labels such as "type I'' and "type II."
Completely out of scope. Hence incorrect

If you negate -C) Properties other than duration are NOT more important than duration in the proper classification of the unusual GRB- then you can see that the argument falls apart, so this one is the correct answer.

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