Which three models of configuration does Cisco Unified Communications Manager Express support? (Choose three.)

Keyswitch mode emulates a traditional key telephone system where multiple lines appear on all phones and users can pick up or hold specific lines directly.

PBX mode provides private branch exchange functionality with internal extensions and feature access codes, supporting the complex call routing typical in enterprise telephony deployments.

Hybrid mode combines both keyswitch and PBX capabilities on a single CME system, allowing some phones to operate as key system phones while others operate as standard PBX extensions.

PSTN describes the public switched telephone network and is a connectivity type, not a CME operational configuration model.

WAN refers to wide area network topology and is not one of the three CME telephony configuration models.

Voice gateway is a device role in the network architecture, not a CME telephony configuration model.

MOH (Music on Hold) is a CME feature for callers placed on hold, not one of the supported configuration models.