Look at all those bits

Which of these is not true about 32-bit and 64-bit architectures?

A) Memory can use a 64-bit bus, even when the CPU is 32-bit

B) A 64-bit data bus can move twice as much as a 32-bit data bus in the same clock cycle

C) Software must be optimized to take advantage of a 64-bit architecture

D) 64-bit applications can run on 32-bit processors

E) 32-bit and 64-bit processors are super awesome