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.

[EX Q]: Problem: a bag contains 10 green and 8 white balls. if two balls are drawn simultaneously, the probability that both are of the same colour is
Options: a. 8 / 15, b. 21 / 44, c. 3 / 5, d. 11 / 15, e. 7 / 15
[EX A]: b

[EX Q]: Problem: a train traveling at 72 kmph crosses a platform in 33 seconds and a man standing on the platform in 18 seconds. what is the length of the platform in meters ?
Options: a. 240 meters, b. 360 meters, c. 420 meters, d. 300 meters, e. can not be determined
[EX A]: d

[EX Q]: Problem: a train 360 m long runs with a speed of 45 km / hr. what time will it take to pass a platform of 140 m long ?
Options: a. 38 sec, b. 35 sec, c. 44 sec, d. 40 sec, e. 48 sec
[EX A]:
d