Task: Question Answering
Input (English): Problem: a bag contains 9 green and 8 white balls . if two balls are drawn simultaneously , the probability that both are of the same colour is 
Options: a ) 8 / 17 , b ) 2 / 5 , c ) 3 / 5 , d ) 11 / 15 , e ) 7 / 15
Output (English): a