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

Ex Input:
Problem: a certain bag contains 100 balls — 50 white , 30 green , 10 yellow , 7 red , and 3 purple . if a ball is to be chosen at random , what is the probability that the ball will be neither red nor purple ? 
Options: a ) 0.9 , b ) 0.75 , c ) 0.6 , d ) 0.8 , e ) 0.5

Ex Output:
a


Ex Input:
Problem: the number of stamps that p and q had were in the ratio of 7 : 4 respectively . after p gave q 8 stamps , the ratio of the number of p ' s stamps to the number of q ' s stamps was 6 : 5 . as a result of the gift , p had how many more stamps than q ? 
Options: a ) 4 , b ) 8 , c ) 12 , d ) 16 , e ) 20

Ex Output:
b


Ex Input:
Problem: what is the greatest positive integer e such that 3 ^ e is a factor of 9 ^ 10 ? 
Options: a ) e = 5 , b ) e = 9 , c ) e = 10 , d ) e = 20 , e ) 30

Ex Output:

d