Which component is required to support Avaya 1600 series IP phones on IP Office?

Avaya 1600 series IP phones (H.323-based) require a DHCP server (Option A) to assign IP addresses and provide the TFTP/HTTP server address for firmware and settings. Option B is for trunks, Option C is for voicemail, and Option D is for resilience—not phone support.References: Avaya IP Office 1600 Series Configuration Guide.