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

Ex Input:
Problem: if 75 percent of a class answered the first question on a certain test correctly , 35 percent answered the second question on the test correctly , and 20 percent answered neither of the questions correctly , what percent answered both correctly ? 
Options: a ) 10 % , b ) ( 8 ) 20 % , c ) 30 % , d ) 50 % , e ) 65 %

Ex Output:
c


Ex Input:
Problem: the compounded ratio of ( 2 : 3 ) , ( 6 : 11 ) and ( 11 : 2 ) is : 
Options: a ) 1 : 2 , b ) 5 : 9 , c ) 2 : 1 , d ) 11 : 24 , e ) none

Ex Output:
c


Ex Input:
Problem: the number of stamps that kaye and alberto had were in the ration of 5 : 3 respectively . after kaye gave alberto 10 of her stamps , the ration of the number of kaye had to the number of alberto had was 6 : 4 . as a result of the gift , kaye had how many more stamps than alberto ? 
Options: a ) 80 , b ) 85 , c ) 65 , d ) 55 , e ) 50

Ex Output:

a