Double Data Rate SDRAM (DDR SDRAM) Chips Are Even Faster

Multiple Choice

Double Data Rate SDRAM (DDR SDRAM) chips are even faster than SDRAM chips because which of the following is true?

A) They transfer data twice for each clock cycle.
B) They are synchronized to the system clock.
C) They do not have to be re-energized as often.
D) They use pipelining techniques.