Excluding stoppages, the speed of a train is 45 kmph and including stoppages it is 35 kmph. Of how many minutes does the train stop per hour? Choose the correct choice from the following answers:
A) 73  B) 83  C) 12  D) 13  E) 28

Rationale: "explanation : t = 10 / 45 * 60 = 13 answer : option d"
Answer: D