Which of the following is IANA responsible for?

The Internet Assigned Numbers Authority (IANA) is responsible for the global coordination of IP addressing and other Internet protocol resources. IANA manages the unallocated global pool of IP addresses and Autonomous System (AS) numbers. Its primary function in this capacity is to allocate large blocks of these number resources to the five Regional Internet Registries (RIRs). The RIRs then handle the subsequent allocation and registration of these resources to Local Internet Registries (LIRs), such as ISPs and large enterprises, within their specific geographical regions.

A. The allocation of enterprise IP address space is handled by Regional or Local Internet Registries (RIRs/LIRs), not directly by IANA.
B. The allocation of residential IP address space is managed by Internet Service Providers (ISPs), which obtain their address blocks from RIRs.
D. The allocation of North American IP address space is the responsibility of ARIN (American Registry for Internet Numbers), the RIR for that region.

1. Nokia Corporation, Nokia Scalable IP Networks Student Guide 4A0-100 R19, Module 1: Internet and L3 Addressing, Section: "IP Address Management". This section details the hierarchical structure of IP address allocation, placing IANA at the top responsible for global allocation to RIRs.

2. Internet Engineering Task Force (IETF), RFC 7020, "The Internet Numbers Registry System", Section 2: "The IANA Function". This document states, "The IANA function is to allocate blocks of numbers to the RIRs from the unallocated number resource pool that is held in reserve by the IANA function operator."

3. IANA (Internet Assigned Numbers Authority), "Number Resources", Official Website. Retrieved from https://www.iana.org/numbers. The site explicitly states: "We are responsible for coordinating the global pool of IP and AS numbers... We allocate blocks of IP addresses and AS numbers to Regional Internet Registries (RIRs)."