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: two trains 180 m and 160 m long run at the speed of 60 km / hr and 40 km / hr respectively in opposite directions on parallel tracks . the time which they take to cross each other is ? 
Options: a ) 10.7 , b ) 10.9 , c ) 10.24 , d ) 12.24 , e ) 18.8

Ex Output:
d


Ex 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

Ex Output:
e


Ex Input:
Problem: a is twice as good as workman as b and together they finish a piece of work in 18 days . in how many days will a alone finish the work ? 
Options: a ) 27 , b ) 26 , c ) 29 , d ) 25 , e ) 24

Ex Output:

a