Given the task definition and input, reply with output. 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: from mumbai railway station, two trains a and b start simultaneously from stations 400 miles apart, and travel the same route toward each other on adjacent parallel tracks. if train a and train b travel at a constant rate of 40 miles per hour and 40 miles per hour, respectively, how many miles will train a have traveled when the trains pass each other, to the nearest mile ?
Options: a. 112, b. 133, c. 150, d. 167, e. 180
e