Which two statements about subnet masks are true?

Which two statements about subnet masks are true? (Choose two.)

A.
If a bit is turned on (1), the corresponding bit in the IP address is used for the host portion.

B.
If a bit is turned off (0), the corresponding bit in the IP address is used for the host portion.

C.
If a bit is turned on (1), the corresponding bit in the IP address is used for the network prefix.

D.
If a bit is turned off (0), the corresponding bit in the IP address is used for the network prefix.

Explanation:
Example: 255.0.0.0 (Class A network), in binary 11111111.00000000. 00000000. 00000000
The leftmost octet, 11111111, represents the network prefix, while the other three octets, with zeroes,
represent the host portion.
http://www.akadia.com/services/ip_routing_on_subnets.html