When Installing Processors with Mixed Stepping Levels in a Server

When installing processors with mixed stepping levels in a server, which of the following guidelines must be followed? (Select TWO) .

A) The processors must have different frequencies set to operate.
B) The processor with the highest feature set must be the bootstrap processor.
C) The processors must have different cache sizes set to operate.
D) The processors must have the same cache size set.
E) The processor with the lowest feature set must be the bootstrap processor.