Which additional security measure does Network Address Translation (NAT) provide for computers behind a gateway router?

Which additional security measure does Network Address Translation (NAT) provide for computers behind a gateway router?

A.
It prevents Internet-based computers from connecting directly to computers on the local network.

B.
It prevents computers on a local network from connecting to computers on the Internet.

C.
It allows multiple computers to use a single public IP addresses to access the Internet.

D.
It allows multiple computers to use a single private IP addresses to access the Internet.