What feature on proximity fuzes allows them to function effectively at varying altitudes?

The correct choice indicates that proximity fuzes are equipped with an altitude sensor, which is crucial for their functionality at different altitudes. This feature enables the fuze to detect the changing atmospheric pressure associated with altitude variations, allowing it to determine the optimal moment for detonation. By understanding the altitude, the fuze can adjust its triggering mechanism to ensure that it activates at the appropriate distance from the target, maximizing effectiveness and accuracy.

The altitude sensor plays a vital role in ensuring that the munitions can engage targets regardless of variations in launch and flight conditions, enhancing their operational versatility. This ability to adapt to different altitudes is essential for accounting for various factors such as ground elevation and target movement, which would otherwise complicate calculations for effective detonation timing during a mission.