Which two statements about the spanning-tree bridge ID are true?

A.	It is composed of a 4-bit bridge priority and a 12-bit system ID extension.
B.	The bridge ID is transmitted in the IP header to elect the root bridge.
C.	The system ID extension is a value between 1 and 4095.
D.	It is composed of an 8-bit bridge priority and a 16-bit system ID extension.
E.	The bridge priority must be incremented in blocks of 4096.