Which of the following statements regarding multicast MAC addresses are false?

Statement B is false because the mapping from IPv4 multicast addresses to Layer 2 MAC addresses is a many-to-one relationship, not one-to-one. An IPv4 multicast address has 28 bits available for the group ID, but only the lower 23 bits are mapped to the MAC address. The upper 5 bits are ignored, meaning 32 (2^5) distinct IPv4 multicast group addresses map to the identical multicast MAC address.
Statement C is also false. While the high 24 bits (0x01005E) and the mapping of the lower 23 bits are described correctly, it incorrectly states that the 25th bit is fixed to 1. According to IETF standards, the 25th bit of the MAC address in this mapping is definitively fixed to 0.

A: This statement is true. As a direct consequence of the 5 unmapped bits from the IPv4 multicast address, exactly 32 different IP multicast addresses map to the same multicast MAC address. D: This statement is true. It accurately defines the function of a multicast MAC address, which is to serve as the Layer 2 identifier for a group of devices that have subscribed to a multicast stream.

1. Deering, S. (1989). RFC 1112: Host Extensions for IP Multicasting. IETF. Section 6.4, "IP Multicast Address to Ethernet/FDDI Address Mapping". This document specifies: "The high-order 25 bits of the Ethernet address are 01-00-5E-0...". This confirms the 25th bit is 0 (making statement C false) and that only the low-order 23 bits are used, which leads to the 32-to-1 mapping (making statement A true and B false).

2. Huawei Enterprise Support. (2023). IP Multicast Configuration Guide - IP Multicast Overview. HedEx Documentation for CloudEngine S12700E Series Switches. In the section "IP Multicast Basics > Multicast Address", the documentation states: "The high 24 bits of the MAC address are 0x01005E. The 25th bit is 0... Therefore, 32 IPv4 multicast addresses are mapped to the same MAC address." This official vendor documentation corroborates the findings from RFC 1112.