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

Ex Input:
Problem: the set s consists of 5 numbers : { 1 , 2,3 , 4,5 } . if all possible subsets including the null set are created and one subset is chosen at random , what is the probability that the subset has 3 or 4 as its largest number ? 
Options: a ) 3 / 4 , b ) 3 / 8 , c ) 3 / 16 , d ) 5 / 16 , e ) 3 / 32

Ex Output:
b


Ex Input:
Problem: what is the probability that a number selected from number 1 to 30 is prime number , when each of the given numbers is equally likely to be selected ? 
Options: a ) 10 / 30 , b ) 20 / 30 , c ) 1 , d ) 5 / 30 , e ) 15 / 30

Ex Output:
a


Ex Input:
Problem: how many cubes of 5 cm edge can be cut out of a cube of 20 cm edge 
Options: a ) 36 , b ) 64 , c ) 216 , d ) 484 , e ) none of these

Ex Output:

b