Although Caps, Floors, and Collars Can Be Created by Buying

Although caps, floors, and collars can be created by buying and selling options on financial futures, this strategy is difficult because

A) exchange-traded options with sufficiently long maturities may not exist, or are illiquid, or are too expensive.
B) these strategies limit the options of banks who use them.
C) regulators prefer swaps to options.
D) they can be used to hedge the $GAP, but not the duration gap.