Correct Answer: B
Border Gateway Protocol (BGP) is a protocol that is often used between gateway hosts on the Internet. A gateway host is a network device that connects two or more different networks, such as a router or a firewall. BGP is a routing protocol that exchanges routing information between autonomous systems (ASes), which are groups of networks under a single administrative control.
BGP is used to determine the best path to reach a destination network on the Internet, based on various factors such as hop count, bandwidth, latency, and policy. BGP is also used to implement interdomain routing policies, such as traffic engineering, load balancing, and security. BGP is the de facto standard for Internet routing and is widely deployed by Internet service providers (ISPs) and large enterprises.