Q: Given a math problem with context and a question and 5 answer choices, the task is to provide the correct answer choice based on the problem. You must choose one of the given answer choices by letter: a, b, c, d, or e; anything else is invalid.
Problem: a bag contains 3 red, 5 yellow and 4 green balls. 3 balls are drawn randomly. what is the probability that the balls drawn contain balls of different colours ?
Options: a. 2 / 7, b. 3 / 5, c. 3 / 11, d. 1 / 4, e. 7 / 16
A:
c