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.
Q: Problem: a train covers a distance of 12 km in 10 minutes. if it takes 8 seconds to pass a telegraph post, then the length of the train is
Options: a. 100 m, b. 120 m, c. 140 m, d. 160 m, e. 170 cm
A:
d