A Primary Difference Between the Trade Winds and Doldrums Is

A primary difference between the trade winds and doldrums is that the trade winds __________, whereas the doldrums __________ .

A) constitute tropical surface flow; constitute a lack of surface flow
B) form in the tropical latitudes; form in deserts
C) constitute a lack of surface flow; constitute tropical surface flow
D) form in the upper atmosphere; form in the polar latitudes