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: a and b can do a work in 12 days , b and c in 15 days , c and a in 20 days . if a , b and c work together , they will complete the work in : 
Options: a ) 5 days , b ) 7 5 / 6 days , c ) 10 days , d ) 15 2 / 3 days , e ) none of these
Example Output: c

Example Input: Problem: one hour before john started walking from p to q , a distance of 23 miles , ann had started walking along the same road from q to p . ann walked at a constant speed of 3 miles per hour and john at 2 miles per hour . how many miles had ann walked when they met ? 
Options: a ) 6 miles , b ) 8,4 miles , c ) 9 miles , d ) 9,6 miles , e ) 15 miles
Example Output: e

Example Input: Problem: the speed at which a man can row a boat in still water is 20 kmph . if he rows downstream , where the speed of current is 4 kmph , what time will he take to cover 80 metres ? 
Options: a ) 10.51 , b ) 11.51 , c ) 9.51 , d ) 13.51 , e ) 15.51
Example Output:
a