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: what is the units digit of 31 ! + 50 ! + 2 ! + 3 ! ?
Options: a ) 0 , b ) 2 , c ) 4 , d ) 6 , e ) 8

Output: e

Input: Consider Input: Problem: a dog takes 3 leaps for every 7 leaps of a hare . if one leap of the dog is equal to 3 leaps of the hare , the ratio of the speed of the dog to that of the hare is :
Options: a ) 9 : 7 , b ) 9 : 9 , c ) 9 : 6 , d ) 9 : 1 , e ) 9 : 2
Output: a