Night duty should not normally be performed by the running staff for more than ________ nights at a stretch. A. 10 B. 12 C. 06 D. None of these

The correct answer is C. 06.

Night duty should not normally be performed by the running staff for more than 6 nights at a stretch. This is because night duty can be physically and mentally demanding, and it is important for staff to have adequate rest in order to perform their duties safely and effectively.

Option A is incorrect because it is too long. Option B is incorrect because it is too short. Option D is incorrect because it is not a specific number of nights.