Question: During the fall time shift from 02:00 to 01:00, how many times will a clock show the times between 01:00:00 and 01:59:59?
Answer: The length of the calendar day becomes variable; it is no longer always 24 hours.
A single-select problem: Is the question answered in a satisfactory fashion?

Pick your answer from:
(a). yes;
(b). no;
(b).