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

Ex Input:
Problem: a bag holds 3 red marbles and 3 green marbles . if you removed two randomly selected marbles from the bag , without replacement , what is the probability that both would be green ? 
Options: a ) 1 / 10 , b ) 1 / 6 , c ) 3 / 10 , d ) 1 / 5 , e ) 1 / 2

Ex Output:
d


Ex Input:
Problem: in a certain alphabet , 16 letters contain a dot and a straight line . 30 letters contain a straight line but do not contain a dot . if that alphabet has 50 letters , all of which contain either a dot or a straight line or both , how many letters contain a dot but do not contain a straight line ? 
Options: a ) 4 , b ) 8 , c ) 12 , d ) 16 , e ) 20

Ex Output:
a


Ex Input:
Problem: how many days per calendar year is the month a factor of the day 
Options: a ) 0 , b ) 1 , c ) 59 , d ) 90 , e ) 124

Ex Output:

e