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'.

Input: Consider Input: Problem: the sum of two consecutive integers is 61 . find the numbers . 
Options: a ) 17 , 18 , b ) 30,31 , c ) 5 , 6 , d ) 1 , 2 , e ) 8 , 9

Output: b


Input: Consider Input: Problem: two trains 180 m and 160 m long run at the speed of 60 km / hr and 40 km / hr respectively in opposite directions on parallel tracks . the time which they take to cross each other is ? 
Options: a ) 10.7 , b ) 10.9 , c ) 10.24 , d ) 12.24 , e ) 18.8

Output: d


Input: Consider Input: Problem: if 18 bindres bind 900 books in 10 days , how many binders will be required to bind 660 books in 12 days ? 
Options: a ) 71 , b ) 12 , c ) 18 , d ) 11 , e ) 29


Output: d