The primary purpose of Network Address Translation is to allow multiple devices on a local network to access the internet using a single public IP address. This conserves the number of IP addresses required and provides an additional layer of security by masking internal IP addresses from external networks. NAT translates the private IP addresses to a public address for outbound traffic, and the public address back to the private addresses for inbound responses. Incorrect answers may sound plausible but they do not correctly describe the primary function of NAT.