What information can you extract having the IP address 172.16.99.45? (Choose two answers.)

(A) The network ID is 172.0.0.0.
(B) The default mask for the network is 255.255.255.0.
(C) The network is a Class B network.
(D) The number of host bits in the unsubnetted network is 16.
(E) The broadcast address of the network is 172.255.255.255.

C and D are the correct answers.

The first octet (172) is in the range of values for Class B addresses (128–191). As a result, the network ID can be formed by copying the first two octets (172.16) and writing 0s for the last two octets (172.16.0.0). The default mask for all Class B networks is 255.255.0.0, and the number of host bits in all unsubnetted Class B networks is 16.