In most states, elections for state offices are usually held a) only in the years presidential elections are held b)three days after all absentee ballots are in c) when all voter registration issues are resolved d) on the same day congress sets for national elections

I believe the answer is: d) on the same day congress sets for national elections

Voters tend to avoid voting if it somehow become a hindrance to their daily schedule. Because of this, the committee tend to compress the voting time range as close as possible in order to obtain the maximum amount of voter turnout.

This link explains it