Assertion (A): Human populations show a great deal of variation in traits.
Reason (R): All variations in a species have equal chances of surviving in the environment in which they live.
A) Both A and R are true, and R is the correct explanation of A.
B) Both A and R are true, but R is not the correct explanation of A.
C) A is true, but R is false.
D) A is false, but R is true.