Concept: The question tests on the basics of Rates(Time and Speed)

Solution:

Without stoppage he travels 48 km in 60 minutes. Therefore he travels 1 km every 60/48 = 5/4 minutes

With stoppage he travels 40 km in 1 hour.

To travel 40 km, he requires 40 * (5/4) = 50 minutes

Therefore his stoppage time is 60 - 50 = 10 minutes

Option B