In this task, you need to provide the correct option for a given problem on probability from the provided options.
Example: Problem: in a throw of a coin find the probability of getting a tail ? 
Options: a ) 1 / 2 , b ) 1 / 3 , c ) 1 / 4 , d ) 2 / 5 , e ) 2 / 7
Example solution: a
Example explanation: "s = { h , t } e = { t } p ( e ) = 1 / 2 answer is a"

Problem: Problem: there are 4 books on a shelf , of which 3 are paperbacks and 6 are hardbacks . how many possible selections of 4 books from this shelf include at least one paperback ? 
Options: a ) a ) 40 , b ) b ) 45 , c ) c ) 50 , d ) d ) 55 , e ) e ) 111

Solution: e