BGP (Border Gateway Protocol) is the only dynamic routing protocol used across the internet. It's classified as an Exterior Gateway Protocol (EGP), responsible for routing between different autonomous systems (ASes).
A: EIGRP and D. OSPF are Interior Gateway Protocols (IGPs), used within organizations.
C: RIP is an outdated IGP with limited use, unsuitable for internet-scale routing.
# Reference:
CompTIA Network+ N10-009 Official Objectives: 3.1 - Compare and contrast various routing technologies.