In this task, you need to provide the correct option for a given problem from the provided options.

Input: Consider Input: Problem: on a certain farm the ratio of horses to cows is 5 : 1 . if the farm were to sell 15 horses and buy 15 cows , the ratio of horses to cows would then be 17 : 7 . after the transaction , how many more horses than cows would the farm own ? 
Options: a ) 30 , b ) 40 , c ) 50 , d ) 60 , e ) 70

Output: c


Input: Consider Input: Problem: evaluate 50 ! / 47 ! 
Options: a ) 102500 , b ) 112584 , c ) 117600 , d ) 118450 , e ) 128450

Output: c


Input: Consider Input: Problem: among 600 students , 56 % study sociology , 44 % study mathematics and 40 % study biology . if 30 % of students study both mathematics and sociology , what is the largest possible number of students who study biology but do not study either mathematics or sociology ? 
Options: a ) 30 , b ) 90 , c ) 120 , d ) 172 , e ) 180


Output: e