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

Ex Input:
Problem: x , y , and z are all unique numbers . if x is chosen randomly from the set { 6 , 7 , 8 , 9 , 10 , 11 } and y and z are chosen randomly from the set { 20 , 21 , 22 , 23 } , what is the probability that x and y are prime and z is not ? 
Options: a ) 1 / 5 , b ) 3 / 20 , c ) 2 / 15 , d ) 1 / 12 , e ) 1 / 10

Ex Output:
d


Ex Input:
Problem: when two dice are rolled , what is the probability that the sum is either 7 or 11 ? 
Options: a ) 1 / 4 , b ) 1 / 9 , c ) 4 / 3 , d ) 3 / 9 , e ) 2 / 9

Ex Output:
e


Ex Input:
Problem: five 6 faced dice are thrown together . the probability that all the three show the same number on them is ? 
Options: a ) 1 / 32 , b ) 1 / 1296 , c ) 1 / 33 , d ) 1 / 38 , e ) 1 / 34

Ex Output:

b