Final answer:
Kin selection is a measure of reproductive fitness of an individual without the help of others, involving the increase of one's own reproductive success by helping relatives. It is a form of indirect fitness.
Step-by-step explanation:
Kin selection refers to a measure of the reproductive fitness of an individual without the help of others. It is the process by which individuals increase their own reproductive success by helping their relatives, who share some of their genes, survive and reproduce. This behavior is considered to be a form of indirect fitness, as it increases the likelihood of passing on shared genes to future generations. Therefore, the correct answer to this question is D) kin selection.