Task: Question Answering
Input (English): Problem: excluding the stoppages , the speed of a bus is 12 km / hr and including the stoppages the speed of the bus is 6 km / hr . for how many minutes does the bus stop per hour ? 
Options: a ) 15 min , b ) 30 min , c ) 12 min , d ) 20 min , e ) 18 min
Output (English): b