A technician is upgrading the memory in a server. The server requires DDR3 Registered DIMMs. The server has four banks of three slots for memory and currently there is one 2GB module in each bank. When the technician attempts to add eight more 4GB modules of DDR3 unbuffered ECC memory, the memory does not fit in the slots. Which of the following is the cause of this issue?
A. In a bank, 2GB and 4GB memory cannot be mixed.
B. The server cannot use ECC memory.
C. The server requires fully buffered memory.
D. The total memory on the server cannot exceed 24GB of RAM.