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 { 5 , 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 ) 1 / 7 , d ) 2 / 15 , e ) 3 / 28

Ex Output:
e


Ex Input:
Problem: how many different ways can 2 students be seated in a row of 7 desks , so that there is always at least one empty desk between the students ? 
Options: a ) 2 , b ) 3 , c ) 30 , d ) 6 , e ) 12

Ex Output:
c


Ex Input:
Problem: find the probability that a leap year selected at random will have 53 sundays 
Options: a ) 6 / 7 , b ) 5 / 7 , c ) 4 / 7 , d ) 3 / 7 , e ) 2 / 7

Ex Output:

e