The most likely reason that a dictator would run in a rigged election is to give the appearance of a democracy. Option A is correct.
The purpose od a dictator running in a rigged election would be to control the outcome of the election, in in way that the dictator ensure his victory in a election that should seem to be a free & fair election .
A dictator is a political leader who possesses absolute power, and a dictatorship is the state under his power and control.