What component controls the ambient air supply for breathing in case of OBOGS failure?

The correct response is rooted in the specific role of the anti-suffocation valve in the context of On-Board Oxygen Generating Systems (OBOGS). This component is crucial for ensuring that pilots have an adequate supply of air necessary for breathing, especially in the event of an OBOGS failure, when the system designed to provide oxygen becomes inoperative.

The anti-suffocation valve is designed to maintain a supply of ambient air to the user, thus preventing potentially life-threatening situations where the pilot might otherwise suffer from hypoxia due to lack of oxygen. It effectively acts as a fail-safe, automatically providing ambient air as an alternative to the primary oxygen supply when needed.

Other components mentioned, while they play roles in oxygen management and aircraft systems, do not specifically handle the ambient air supply in the same urgent manner that the anti-suffocation valve does during an OBOGS failure.