The answer is D. BGP . When a company wants a redundant internet connection , especially across more than one external path or provider, Border Gateway Protocol (BGP) is the routing technology most commonly associated with that design. BGP is used between autonomous systems and is the standard protocol for making routing decisions across the internet or between an organization and one or more ISPs.
The other options are interior routing protocols. EIGRP , RIPv2 , and OSPF are generally used inside an organization to exchange routes within a private network environment. They are not the normal answer when the question specifically says internet connection redundancy . That wording points outward, beyond the internal LAN or campus routing domain.
In practical terms, BGP gives administrators a way to influence path selection, advertise network prefixes, and maintain reachability if one outside connection fails. That is why it appears in questions involving multihoming, ISP failover, or resilient edge connectivity. Since the scenario mentions redundant firewalls and a need for a redundant internet connection, the best match is the routing technology designed for external route exchange. For Network+, that technology is BGP .