In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Example Input: Problem: a van takes 6 hours to cover a distance of 180 km . how much should the speed in kmph be maintained to cover the same direction in 3 / 2 th of the previous time ?
Options: a ) 50 kmph , b ) 60 kmph , c ) 70 kmph , d ) 80 kmph , e ) 20 kmph
Example Output: e

Example Input: Problem: a man swims downstream 76 km and upstream 48 km taking 4 hours each time ; what is the speed of the current ?
Options: a ) 3 kmph , b ) 1.5 kmph , c ) 3.5 kmph , d ) 6.5 kmph , e ) 7 : 3 kmph
Example Output: c

Example Input: Problem: how many times are the hands of a clock at right angle in 2 days ?
Options: a ) 80 , b ) 82 , c ) 84 , d ) 86 , e ) 88
Example Output:
e