Excluding stoppages, the speed of a bus is 90 km/hr and including stoppages, it is 84 km/hr. For how many minutes does the bus stop per hour?
Choose the correct choice from the following choices: A) 18 min B) 4 min C) 8 min D) 6 min E) 5 min

Rationale: "due to stoppages , it covers 6 km less . time taken to cover 6 km = 6 / 90 * 60 = 4 min . answer : b"
Answer: B