BGMP stands for border gateway multicast protocol. It is used for inter-domain multicast routing and natively
supports "source-specific multicast" (SSM). In order to support "any-source multicast" (ASM), BGMP builds
shared trees for active multicast groups. This allows domains to build source-specific, inter-domain, distribution
branches where needed. BGMP uses TCP as its transport protocol, which helps in eliminating the need to
implement message fragmentation, retransmission, acknowledgement, and sequencing.
Answer option B is incorrect. The Distance Vector Multicast Routing Protocol (DVMRP) is used to share
information between routers to transport IP Multicast packets among networks. It uses a reverse path-flooding
technique and is used as the basis for the Internet's multicast backbone (MBONE). In particular, DVMRP is
notorious for poor network scaling, resulting from reflooding, particularly with versions that do not implement
pruning. DVMRP's flat unicast routing mechanism also affects its capability to scale.
Answer option D is incorrect. EIGRP is a Cisco proprietary protocol. It is an enhanced version of IGRP. It has
faster convergence due to use of triggered update and saving neighbor's routing table locally. It supports VLSM
and routing summarization. As EIGRP is a distance vector protocol, it automatically summarizes routes across
Class A, B, and C networks. It also supports multicast and incremental updates and provides routing for three
routed protocols, i.e., IP, IPX, and AppleTalk.
Answer option C is incorrect. Open Shortest Path First (OSPF) is a routing protocol that is used in large
networks. Internet Engineering Task Force (IETF) designates OSPF as one of the Interior Gateway Protocols.
A host uses OSPF to obtain a change in the routing table and to immediately multicast updated information to
all the other hosts in the network.

The IP address range from 0.0.0.0 to 127.255.255.255 falls under Class A. In the Class A type of network, the first octet (the first 8 bits of the IP address) is used for the network part, and the remaining 24 bits are used for host addresses. The default subnet mask for Class A is 255.0.0.0, which aligns with the given network's default subnet mask. Class A networks are designed to support a very large number of hosts. The first bit of a Class A address is always set to 0, which means the first octet can range from 1 to 127, thus including the given IP address range.
References: This explanation is based on standard networking principles regarding IP address classes as outlined in resources like the Meridian Outpost article on IPv4 address classes1, and is consistent with the objectives and documents of the EC-Council's Certified Network Defender (CND) program.