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'.

Ex Input:
Problem: x can finish a work in 20 days . y can finish the same work in 15 days . yworked for 9 days and left the job . how many days does x alone need to finish the remaining work ? 
Options: a ) 3 , b ) 5 , c ) 6 , d ) 8 , e ) 9

Ex Output:
d


Ex Input:
Problem: two trains a and b are 125 m and 150 m long and are moving at one another at 54 km / hr and 36 km / hr respectively . arun is sitting on coach b 1 of train a . calculate the time taken by arun to completely cross train b . 
Options: a ) 10 s , b ) 11 s , c ) 4 s , d ) 8 s , e ) 12 s

Ex Output:
b


Ex Input:
Problem: pipe a can fill a tank in 3 hours . due to a leak at the bottom , it takes 9 hours for the pipe a to fill the tank . in what time can the leak alone empty the full tank ? 
Options: a ) 4.5 , b ) 17 , c ) 18 , d ) 19 , e ) 12

Ex Output:

a