Hey Soumita,

Let's start with a brief outline of the argument:

Conclusion: # of Post-grads in physics is gonna go down
Proof: Fewer students are choosing a career in physics

The assumption here is fairly straightforward. A lot of people study fields even if they don't want/expect a career in that field (the liberal arts are the best example of this, but it applies to science, too). This argument assumes that the # of physics jobs correlates with the # of physics post-grads.

A) The argument links jobs to folks doing post-grads, not jobs to undergrads or undergrads to post-grads.

B) This is irrelevant. Knowing about chemistry tells us nothing about physics.

C) CORRECT. This answer breaks the correlation between # of postgrads in physics and # of career physicists. If most postgrads in physics don't go into physics anyway, then it follows that a change in one statistic (# of career physicists) won't affect the other statistic (# of physics postgrads).

D) This is tempting, but an increase in professors does not necessitate an increase in postgrads. They could simply be improving the teacher to student ratio.

E) The severity of the cutbacks isn't important. We already know there have been cutbacks. The question is whether the assumed result of those cutbacks (fewer career physicists) necessarily affects the # of physics postgrads.

Hope that helps!

-t