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: a man can row upstream at 26 kmph and downstream at 30 kmph , and then find the speed of the man in still water ? 
Options: a ) 29 , b ) 28 , c ) 30 , d ) 32 , e ) 23

Ex Output:
b


Ex Input:
Problem: it takes joey the postman 1 hours to run a 7 mile long route every day . he delivers packages and then returns to the post office along the same path . if the average speed of the round trip is 8 mile / hour , what is the speed with which joey returns ? 
Options: a ) 11 , b ) 12 , c ) 13 , d ) 8 , e ) 15

Ex Output:
d


Ex Input:
Problem: the sector of a circle has radius of 21 cm and central angle 270 o . find its perimeter ? 
Options: a ) 145 cm , b ) 135 cm , c ) 121 cm , d ) 141 cm , e ) 151 cm

Ex Output:

d