How many SSBs can there be in a fully configured server?

There are 16x CMUs and 4x IOUs with up to 4x DCUs in a fully configured SPARC M5-32 server. The core interconnect component is Scalability Switch Board
(SSB). How many SSBs can there be in a fully configured server?

A.
16

B.
4

C.
20

D.
12