A memory unit has two control inputs labeled enable and read/write. The memory data inputs and outputs are connected to an MBR registers in figure 8.7. The MBR can receive information either from an external register EXR or from the memory unit after a read operation. The MBR provides the data for the memory-write operation. Draw a block diagram using multiplexers and gates that shows the connection of MBR to memory. The system must have a capability of implementing the following three transfers: W:MMBR R:MBRM E: MBREXR