In addition to the localizer, glide slope, marker beacons, approach lighting, and HIRL, which components are required to operate for a Category II instrument approach to a DH below 150 feet AGL?

In a Category II instrument approach, maintaining a safe landing in low visibility conditions is critical, and certain systems must be operable to ensure this safety. The correct answer emphasizes that each required ground component must be functional. These components include the localizer, glide slope, and other specialized systems that enhance aircraft guidance and visibility during the approach.

The Category II requirements are designed to support approaches with decision heights (DH) as low as 100 feet AGL. For such approaches, the overall integrity and functionality of all specified ground systems are essential to provide the necessary lateral and vertical guidance to the aircraft. If any of these components were inoperative, it would compromise the safety and efficacy of the approach and landing, potentially putting the aircraft and its passengers at risk.

While the other choices may refer to specific systems or components, they do not encompass the breadth of operational requirements that must be met for a Category II approach. Each ground component's operational status is vital for successful and safe landings under such challenging conditions.