Which of the following technologies allows more than two transceivers with an access point?

MIMO is an antenna technology defined in the 802.11n and later standards that uses multiple transmit and receive antennas - often 2x2, 3x3, or 4x4 configurations - to transmit and receive multiple data streams at the same time. This spatial multiplexing significantly increases throughput compared to single-antenna (SISO) designs.

FIFO (First In, First Out) is a queue management or data structure concept, not a wireless transceiver technology.

802.1x is a port-based network access control (authentication) standard, not a technology related to the number of wireless transceivers.

WPA (Wi-Fi Protected Access) is a wireless security and encryption protocol and has nothing to do with the number of transceivers on an access point.