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: the ratio between the speeds of two trains is 7 : 8 . if the second train runs 400 km in 4 hours , what is the the speed of the first train ? 
Options: a ) 87.0 , b ) 87.5 , c ) 87.2 , d ) 87.1 , e ) 87.4

Ex Output:
b


Ex Input:
Problem: a contractor undertakes to built a walls in 50 days . he employs 20 peoples for the same . however after 25 days he finds that only 40 % of the work is complete . how many more man need to be employed to complete the work in time ? 
Options: a ) 25 , b ) 30 , c ) 35 , d ) 30 , e ) none of these

Ex Output:
d


Ex Input:
Problem: a person can row at 9 kmph and still water . he takes 8 1 / 2 hours to row from a to b and back . what is the distance between a and b if the speed of the stream is 1 kmph ? 
Options: a ) 32 , b ) 38 , c ) 29 , d ) 54 , e ) 20

Ex Output:

b