Task: Question Answering
Input (English): Problem: an urn contains 5 red, 6 blue and 8 green balls. 3 balls are randomly selected from the urn, find the probability that the drawn ball are blue ?
Options: a. 20 / 969, b. 20 / 875, c. 21 / 876, d. 3 / 512, e. 2 / 9
Output (English): a