X: Medical research on animals should not be reduced in response to a concern for animals, because results of such research serve to avert human suffering. In such research a trade-off between human and animal welfare is always inevitable, but we should give greater weight to human welfare.

Y: With technology that is currently available, much of the research presently performed on animals could instead be done with computer modeling or human subjects without causing any suffering.

The relationship of Y’s response to X’s argument is that Y’s response

(A) contradicts a premise on which X’s argument relies
(B) disagrees with X about the weight to be given to animal suffering as opposed to human suffering
(C) presents a logical consequence of the premises of X’s argument
(D) strengthens X’s argument by presenting evidence not mentioned by X’s argument
(E) supplies a premise to X’s argument that was not explicitly stated
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My Approach:
X is basically saying animals will have to suffer because we human welfare has greater weight-age.
Y is saying No. Not necessarily true. there is technology available with which you can do the research.

Question: Y -> X? In one word "disagreement"

A. Is Y contradicting ? Yes. on which X's argument relies.? Yes. If you re-read both statements above you will agree too
E. supplies a premise to X's argument? Okay May be. that was not explicitly stated? No. That's not the tone of X. If X were to continue saying, he won't say But may be animal suffering is not inevitable because he already has used such a strong word.
B. They are not comparing weight given to animal suffering.
D. No. Does not strengthen
C. Y's response is not a consequence. You can think of consequence of X's argument being on the lines of If animals die then something bad can happen or something like that. Not true.

IMO A.
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