How did the county unit system support segregation?

Responses
A It encouraged the practice of buying votes.It encouraged the practice of buying votes.
B It permitted only white males to run for public office.It permitted only white males to run for public office.
C It allowed urban counties to decide whether to enforce segregation or not.It allowed urban counties to decide whether to enforce segregation or not.
D It gave rural counties, which were more conservative, more representation.It gave rural counties, which were more conservative, more representation.

A It encouraged the practice of buying votes.