Task: Question Answering
Input (English): Problem: the diameter of the driving wheel of a bus in 140 cm . how many revolutions per minute must the wheel make in order to keep a speed of 20 kmph ? 
Options: a ) 21.21 , b ) 20.25 , c ) 32.25 , d ) 75.75 , e ) 62.61
Output (English): d