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

Example Input: Problem: a bag contains 10 black and 20 white balls . one ball is drawn at random . what is the probability that the ball drawn is white ? 
Options: a ) 1 / 2 , b ) 3 / 4 , c ) 2 / 3 , d ) 1 / 5 , e ) 3 / 7
Example Output: c

Example Input: Problem: the main line train starts at 5.00 am and the harbor line train starts at 5.02 am . each train has the frequency of 10 minutes . if a guy goes in the morning at a random time what is the probability of he getting main line train ? 
Options: a ) . 5 , b ) 0.6 , c ) 0.4 , d ) 0.7 , e ) 0.8
Example Output: e

Example Input: Problem: in how many ways 4 boys and 1 girls can be seated in a row so that they are alternate . 
Options: a ) 144 , b ) 288 , c ) 24 , d ) 256 , e ) none
Example Output:
c