Which architecture does not require an explicit multicast signaling protocol, such as PIM or P2MP,...

Bit Indexed Explicit Replication (BIER) eliminates the need for traditional multicast signaling protocols such as PIM.

BIER uses IGP extensions (e.g., OSPF or ISIS) to advertise BIER forwarding state.

The BIER header contains a bit-string indicating directly which receivers should receive the multicast packet, removing the need to build trees via signaling.

This design is emphasized in CCDE v3.1 as a significant advancement for efficient, scalable multicast in large modern service provider and enterprise networks.

Why other options are incorrect:

A, B, D: These options are invalid or fictitious terms in multicast protocol standards.