At what point can a pilot descend below 5,300 feet when cleared to the AJCIZ waypoint from the west?

The correct choice is based on the standard operating procedures for instrument approaches and the specific regulations governing altitude changes near waypoints. In this scenario, the pilot is authorized to descend below 5,300 feet when approaching the AJCIZ waypoint, but only when they are specifically at a distance from the waypoint that allows for safe maneuvering and compliance with air traffic control instructions.

Typically, descending at a designated distance from a waypoint ensures that the aircraft is at an appropriate altitude for the upcoming segments of the approach, factoring in terrain, obstacles, and airspace requirements. In many approach procedures, a 15 NM distance is a common point where pilots are cleared to descend, provided they maintain situational awareness and adhere to the constraints given during their clearance by air traffic control.

Thus, being 15 NM from the waypoint indicates that the aircraft is properly positioned to begin a descent safely and in accordance with the established procedure.