The phenomenon is taboos against eating animals, and the explanation is the practical value of animals, e.g. for labor. The anthropologist calls it into question by suggesting that the taboos could have arisen first, and then were followed by the practical usage of animals.

The anthropologist doesn’t argue that the explanation is false, only that it could be false.

The anthropologist doesn’t say that the other hypothesis is more plausible, only that it’s also plausible.

The anthropologist argues that the evidence could support an alternative explanation, not that it’s incompatible with the original explanation. His argument is that two different hypotheses are consistent with the same set of facts.

The anthropologist doesn’t argue that the events did occur in a different sequence, only that they could have occurred in a different sequence. Like (C) and (B), this is overstating the anthropologist’s belief.