What is meant by "physiological night's rest"?

The term "physiological night's rest" refers to the concept of rest that aligns with the body's natural circadian rhythms and sleep cycles. The correct choice indicates a requirement for 10 hours of rest that specifically includes the period between 0100 and 0700 at the crew member's home base. This time frame is significant because it tends to coincide with the body's biological peak for restorative sleep, enhancing overall alertness and performance during flight operations.

A full 10 hours allows for a sufficient amount of sleep, taking into consideration the time needed to fall asleep and any potential disturbances. This recommendation is aimed at ensuring that crew members are well-rested and can safely perform their duties, minimizing the risk of fatigue-related incidents.

While other choices present varying durations and conditions of rest, they do not encapsulate the optimal alignment with the natural sleep cycle and physiological needs, which is paramount for maintaining safety in aviation operations.