Every fall Croton's jays migrate south. The jays always join flocks of migrating crookbeaks with which they share the summer and winter territories. If a jay becomes separated from the crookbeaks it is accompanying, it wanders until it comes across another flock of crookbeaks. Clearly, therefore, Croton's jays lack the navigational ability to find their way south on their own.

Which of the following, if true, most strengthens the argument above?
A - Croton's jays lay their eggs in the nest of crookbeaks, which breed upon completing their southern migration.
B - The three species of most closely related to crookbeaks do not migrate at all.
C - In the spring, Croton's jays migrate north in the company of Tattersall warblers.
D - Species other than Croton's jays occasionally accompany flocks of migrating crookbeaks.
E - In the spring, crookbeaks migrate north before Croton's jays do.



Not a clue for the rhyme or reason why the OA is what it is. Anyone care to shed some light?

Here is why the answer is C.

The premise they want us to strengthen is that these C Jay birds lack the ability to find their way on their own. C is the only one that strengthes this premise.

C says (C) In the spring, Croton’s jays migrate north in the company of Tattersall warblers.

If these birds also migrate following another type of bird this supports the premise that they cannot find the way on their own.

The reason it is not A is because -

A says Croton’s jays lay their eggs in the nest of crookbeaks, which breed upon completing their southern migration. Well, this provides a different reason as to why they would follow the crookbreaks. They might be following them because they are waiting for their young to be born, not because they lack the navigational ability to find their way south on their own.


The reason it is not B is because -
B says B) The three species of most closely related to crookbeaks do not migrate at all

This is irelevant and has nothing to do with the argument.

The reason it is not D is because -

D says, (D) Species other than Croton’s jays occasionally accompany flocks of migrating crookbeaks.

This statement does not strengthen the premise that Croton Jays' can't follow directions. It actually weaknes that premise because it shows that other birds also follow these birds, so it is not a specific condition for the the C Jays.

E is not the answer, because it is not relevant to the question

I hope these help explanations help!

I would probably pick C, uncomfortably.

A is the best
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Got C as well.

Only answer that says CJ needs company to go any where. Probably because they cant navigate by themselves.

OA & OE?

^^Thanks for clarifying. Your explanation helped burn the fog away.

OA: C

I picked A. can anybody explain what wrong with it. May be the eggs hatch and give birth to young ones who dont know the navigation. [:P]

Good explanation....

Its a clear C... they need navigation
so to strengthen, they need a navigator, in spring other birds provide the navigation

Strenthning leadership of CB does not necessarly leads to argument that CJ lacks navigation ability.

Option C further strenthens the argument that CJ is weak for its navigation ability.