Answer: Option D
Step-by-step explanation:
The hypothesis is to test whether hair length is heritable or not. The cotton topped tamarins are primates in which some of the individuals have long hair and some of them have short hair.
They have tufts of long white hair on their head and the males that have longer hair get more chances to mate.
In this process, the hypothesis was based on the fact that whether the length of hair is a heritable trait or not.