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

Ex Input:
Problem: in 15 year ’ s time the combined age of my 4 brothers will be 107 . what will it be in 6 year ’ s time ? 
Options: a ) 65 , b ) 87 , c ) 71 , d ) 60 , e ) 66

Ex Output:
c


Ex Input:
Problem: a meeting has to be conducted with 5 managers . find the number of ways in which the managers may be selected from among 8 managers , if there are 2 managers who refuse to attend the meeting together . 
Options: a ) 36 , b ) 40 , c ) 45 , d ) 51 , e ) 56

Ex Output:
a


Ex Input:
Problem: there are 7 books on a shelf , of which 2 are paperbacks and 5 are hardbacks . how many possible selections of 4 books from this shelf include at least one paperback ? 
Options: a ) a ) 30 , b ) b ) 45 , c ) c ) 50 , d ) d ) 55 , e ) e ) 60

Ex Output:

a