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

Input: Consider Input: Problem: a number is selected at random from the first 40 natural numbers . what is the probability that the number is a multiple of either 2 or 21 ? 
Options: a ) 21 / 40 , b ) 2 / 5 , c ) 7 / 15 , d ) 4 / 15 , e ) 11 / 30

Output: a


Input: Consider Input: Problem: three unbiased coins are tossed . what is the probability of getting 3 heads and 1 tail ? 
Options: a ) 3 / 4 , b ) 1 / 4 , c ) 3 / 8 , d ) 1 / 2 , e ) 1 / 8

Output: d


Input: Consider Input: Problem: a bag contains 3 red , 5 yellow and 4 green balls . 3 balls are drawn randomly . what is the probability that balls drawn contain exactly two green balls ? 
Options: a ) 9 / 16 , b ) 7 / 18 , c ) 12 / 55 , d ) 14 / 67 , e ) 19 / 87


Output: c