Why is a Cisco UCS B250 server unable to support 16-GB DIMMs?

A.
Dual-rank DIMMs are not supported.

B.
16-GB DIMMs are too slow.

C.
The largest DIMM an Intel 55xx or 56xx CPU can address is 32 GB.

D.
The memory bus would be too long.

E.
The blade would run too hot.