In buck's thinking, the "noblest" prey of all is a. a very fast rabbit.
b. another dog.
c. a moose.
d. man.

I think the correct answer from the choices listed above is option D. In Buck's thinking, the "noblest" prey of all is a man. It can be found in Chapter 7 where it was said that "He had killed man, the noblest game of all, and he had killed in the face of the law of club and fang."

Idon’t know who knows i do know who does not know me