Saying that it’s “always required” is too strong. Although mortality patterns were used in this case, that doesn’t imply that they always need to be used in order to establish whether a prehistoric culture domesticated animals.

Too strong. We have no reason to think that corroboration by evidence at a similar site is required in order for evidence at another site to be conclusive. Just because Olsen examined multiple sites does not imply that one always needs to examine multiple sites in order for the conclusions from one site to be reliable.

Not supported, because the author doesn’t suggest that the Botai’s potential arranging of horse bones implies a “high level of social organization.” The author suggests the arranging implies a purpose beyond just hunting, but this doesn’t require any belief about the social organization of the Botai society.

Supported. As part of interpreting the bones she found, Olsen takes into account the habits of horses as well as the habits of herders of domesticated animals. How horses typically group together in the wild and how herders typically kill off animals are not facts that are determinable from the bones at an excavation site.

The word “often” is important in this answer; if it had said “always,” (D) would not be supported.

Not supported, because the author doesn’t make any claims about the relative ease or difficulty of domesticating some animals over others.