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: in what time will a train 140 meters long cross an electric pole , if its speed is 210 km / hr 
Options: a ) 5 seconds , b ) 4.5 seconds , c ) 3 seconds , d ) 2.4 seconds , e ) none of these
Example Output: d

Example Input: Problem: a motorcyclist started riding at highway marker a , drove 120 miles to highway marker b , and then , without pausing , continued to highway marker c , where she stopped . the average speed of the motorcyclist , over the course of the entire trip , was 40 miles per hour . if the ride from marker a to marker b lasted 3 times as many hours as the rest of the ride , and the distance from marker b to marker c was half of the distance from marker a to marker b , what was the average speed , in miles per hour , of the motorcyclist while driving from marker b to marker c ? 
Options: a ) 40 , b ) 45 , c ) 50 , d ) 55 , e ) 67.5
Example Output: e

Example Input: Problem: a cistern 12 meters long and 4 meters wide contains water up to a depth of 1 meter 25 cm . what is the total area of the wet surface ? 
Options: a ) 64 , b ) 72 , c ) 80 , d ) 88 , e ) 96
Example Output:
d