Which of the following should be specified to configure the VPN connection?

Explanations:

Classless routing refers to routing that does not rely on fixed classful boundaries (A, B, C), using instead subnet masks to determine network boundaries. While it is relevant in some contexts, BGP does not specifically require classless routing to establish a VPN connection.

Classful routing uses fixed classes (A, B, C) to categorize networks, which is outdated and not suitable for modern networking needs. BGP, as a dynamic routing protocol, is designed to handle classless addressing and does not necessitate classful routing.

Dynamic routing, which includes protocols like BGP, allows routers to automatically adjust to changes in the network. BGP is specifically a dynamic routing protocol that enables the exchange of routing information between autonomous systems (AS), making it essential for configuring VPN connections that leverage BGP.

Static routing involves manually configuring routes, which does not allow for the dynamic adaptability that BGP provides. While static routes can be used in conjunction with dynamic routes, BGP is primarily associated with dynamic routing rather than static routing configurations.