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

Input: Consider Input: Problem: if 4 consecutive letters are selected at random from the english alphabet , then the probability that one of the letters is a vowel is ? 
Options: a ) 13 / 23 , b ) 16 / 23 , c ) 11 / 23 , d ) 17 / 23 , e ) 18 / 23

Output: d


Input: Consider 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 7 managers , if there are 2 managers who refuse to attend the meeting together . 
Options: a ) 6 , b ) 8 , c ) 10 , d ) 11 , e ) 15

Output: d


Input: Consider Input: Problem: when tossed , a certain coin has equal probability of landing on either side . if the coin is tossed 4 times , what is the probability that it will land on the same side each time ? 
Options: a ) 1 / 8 , b ) 1 / 4 , c ) 1 / 16 , d ) 1 / 2 , e ) 1 / 32


Output: a