Task: Question Answering
Input (English): Problem: a bag contains 7 black and 8 white balls. if two balls are drawn simultaneously, what is the probability that both are of the same color is ?
Options: a. 1 / 2, b. 1 / 3, c. 2 / 3, d. 3 / 5, e. 7 / 15
Output (English): e