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'.

Example 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
Example Output: d

Example Input: Problem: a boat m leaves shore a and at the same time boat b leaves shore b . they move across the river . they met at 500 yards away from a and after that they met 300 yards away from shore b without halting at shores . find the distance between the shore a & b 
Options: a ) 1000 yards , b ) 1200 yards , c ) 1400 yards , d ) 1600 yards , e ) 1800 yards
Example Output: b

Example Input: Problem: bob wants to run a mile in the same time as his sister . if bob ’ s time for a mile is currently 10 minutes 20 seconds and his sister ’ s time is currently 9 minutes 36 seconds , by what percent does bob need to improve his time in order run a mile in the same time as his sister ? 
Options: a ) 3 % , b ) 5 % , c ) 7 % , d ) 10 % , e ) 12 %
Example Output:
c