What Do Election Reformers Suggest Concerning State Gubernatorial Elections and Presidential

What do election reformers suggest concerning state gubernatorial elections and presidential elections?

A) They must always be held together to reduce electoral costs.
B) They should be held separately to avoid state politics being swamped by the tides of national politics.
C) They can only be held together if the governor's term is ending in the same year.
D) They must not be held together if both the gubernatorial incumbent and presidential incumbent are from the same party.
E) They can only be held together if the gubernatorial incumbent is not running for reelection.