Access management is closely related to which other process?

Capacity management focuses on ensuring sufficient IT resource throughput to meet demand, and has no direct relationship to granting or revoking user access rights.

3rd line support is a support escalation tier for technically complex incidents, not a process that governs user authorization or access policies.

Access management controls who is authorized to use IT services and ensures those rights are granted and revoked according to policy. Information security management defines those policies and the security framework, so access management is essentially the runtime enforcement arm of information security management. ITIL describes the two as closely linked, with access management implementing the security controls that information security management establishes.

Change management governs the controlled lifecycle of changes to services and infrastructure, not the authorization and enforcement of user access permissions.