X: Medical research on animals should not be reduced in response to a

Hello expert,
I wonder why B is wrong, as A and B almost the same meaning to me.
X says we take animals for test because we should give greater weight to human, while Y says we could use human subjects for instead, so Y does not agree with X to give greater weight to human. And this is what B means to me, so why B is wrong?
Hope to help and thanks in advance.

Here's (B).

(B) disagrees with X about the weight to be given to animal suffering as opposed to human suffering

Notice that Y doesn't say anything about weight to be given to human suffering or animal suffering. Yes, Y mentions using human subjects. At the same time, Y's point is that suffering can be reduced because research can be done "without causing any suffering."

MartyTargetTestPrep thanks for your response expert, but sorry I do not well understand what you mean. Yes Y doesn't directly say anything in his words about weight to be given to human suffering or animal suffering, but I think we can infer his meaning from his words. The post I write is my understanding of Y’s words, so could you tell me where I am wrong?
Also, could you explain why A is correct by comparing A and B? I was confused as A and B almost the same meaning to me: I think “contradicts X’s premise = disagrees with X about the weight“. Mind to explain further? Thanks

Here's Y's response:

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.

Nothing in that response indicates anything about the weight to be given to human or animal suffering. Rather, Y dodges that issue by saying that "much of the research ... could instead be done with ... human subjects without causing any suffering."

We can't take "could instead be done with ... human subjects without causing any suffering" to mean that Y means that greater weight should not be given to human suffering because Y is talking about doing research in ways that involve NO suffering. So, the whole idea of giving greater weight to human or animal suffering doesn't apply to what Y is talking about. After all, we can't give a greater weight to something that doesn't exist at all.

Regarding (A), (A) is correct because what Y says, "research could instead be done with ... without causing any suffering," contradicts what X says, "In such research a trade-off between human and animal welfare is always inevitable."

Y is indicating that "a trade-off between human and animal welfare" is NOT always inevitable because research can be done in ways such that neither animals nor humans suffer. If there is no suffering, then there is no trade-off and no greater weight given to anyone's suffering.

MartyTargetTestPrep Much thanks for your input and patience. Got you and understand now.

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