How will the right answer fit in terms of support and conclusion?

Only the right answer will add support for disagreeing with the conclusion.

Highlight the main conclusion in the passage, if there is one:

all animals can, in principle, be bred for domesticity.

[SUPPORT]. For example, [SUPPORT].Therefore, [CONCLUSION].

The author changes the subject pretty dramatically by bringing “all animals” into the conclusion. The support is only about dogs. The right answer will call out that what works for dogs won’t work for “all animals”.

Map the wording of the answers to the wording of the passage:

(A) Domesticated animals cannot be turned into wild species…

Whoa, nobody said anything about going the other direction. The argument is only about wild animals becoming domesticated, not the other way around.

(B) …wild members mate more frequently…

That’s a lovely mental image. But it’s bringing in a new factor the passage didn’t mention, and that doesn’t immediately seem relevant. You’d have to add in your own reasoning to make this work, which you are not supposed to do.

(C) …no members ever display tameness.

Boom! This sticks to the same issue the passage talks about, and if this is true, then what the author explained about dogs won’t work on “some animal species”.

(D) …tame members are less fertile…

Like (B), this is something the passage doesn’t talk about, and isn’t clearly relevant using only common sense. Eliminated.

(E) …some members are much more tame than other members.

Love that this says more about who’s “tame”, but hate that it’s comparing animals to other animals of the same species. The argument is about using dogs as an example for a conclusion about other species.

(C) is the correct answer.