What is the minimum 'off-duty' sleep required when in a sleeper berth?

The minimum 'off-duty' sleep required when in a sleeper berth is established to ensure that drivers have adequate rest to maintain safety while operating commercial vehicles. In Canada, regulations stipulate that drivers must take at least two consecutive hours of off-duty time in a sleeper berth to comply with safety standards. This period allows for the body to recover from fatigue, which is critical for maintaining alertness and reducing the risk of accidents on the road. Adequate sleep helps to prevent drowsiness and ensures drivers are in the best condition to operate their vehicles safely.

Options that propose one hour, three hours, or four hours do not align with the regulations that specifically mandate a minimum of two hours. While longer rest periods can be beneficial, the minimum requirement set is two hours, hence making it the correct answer for this question.