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: how many seconds will a 1200 m long train take to cross a man walking with a speed of 3 km / hr in the direction of the moving train if the speed of the train is 63 km / hr ?
Options: a ) 26 sec , b ) 65 sec , c ) 55 sec , d ) 19 sec , e ) 72 sec
Example Output: e

Example Input: Problem: if 21 lines are drawn in a plane such that no two of them are parallel and no three are concurrent , then in how many points do they intersect ?
Options: a ) 150 , b ) 170 , c ) 190 , d ) 210 , e ) 230
Example Output: d

Example Input: Problem: a room 3 m 21 cm long and 7 m 77 cm broad is to be paved with square tiles . find the least number of square tiles required to cover the floor .
Options: a ) 27636 , b ) 27640 , c ) 27647 , d ) 27713 , e ) 27675
Example Output:
d