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 distance between a & b is 600 km . a person is traveling from a to b at 70 km / hr started at 10 am and another person is traveling from b to a at 80 km / hr and started at same time . then at what time they meet together . 
Options: a ) 2 pm , b ) 4 pm , c ) 1 pm , d ) 3 pm , e ) 5 pm

Ex Output:
a


Ex Input:
Problem: a boat covers a certain distance downstream in 1 hour , while it comes back in 1 ½ hours . if the speed of the stream be 3 kmph , what is the speed of the boat in still water ? 
Options: a ) 12 kmph , b ) 13 kmph , c ) 14 kmph , d ) 15 kmph , e ) none

Ex Output:
d


Ex Input:
Problem: a can do a job in 18 days and b can do it in 30 days . a and b working together will finish twice the amount of work in days ? 
Options: a ) 29 ½ days , b ) 22 ½ days , c ) 92 ½ days , d ) 28 ½ days , e ) 92 ½ days

Ex Output:

b