Suppose Mutation and Selection No Longer Occurred in a Small

Suppose mutation and selection no longer occurred in a small, isolated population of nematodes.Which process would most likely continue operating, and what would be the most likely effect on the extent of genetic variation?

A) Gene flow would lead to an increase in genetic variation.
B) Gene flow would lead to a decrease in genetic variation.
C) Genetic drift would lead to an increase in genetic variation.
D) Genetic drift would lead to a decrease in genetic variation.
E) Genetic drift would operate but would have no effect on genetic variation.