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 train 150 m long is running at a speed of 68 kmph. how long does it take to pass a man who is running at 8 kmph in the same direction as the train ?
Options: a. 2 sec, b. 6 sec, c. 8 sec, d. 9 sec, e. 5 sec
d

Problem: sandy walked 20 meters towards south. then sandy turned to her left and walked 20 meters. she then turned to her left and walked 20 meters. she then turned to her right and walked 25 meters. what distance is she from the starting point and in which direction ?
Options: a. 35 m east, b. 35 m north, c. 30 m west, d. 45 m west, e. 45 m east
e

Problem: a father and his son are waiting at a bus stop in the evening. there is a lamp post behind them. the lamp post, the father and his son stand on the same straight line. the father observes that the shadows of his head and his son ’ s head are incident at the same point on the ground. if the heights of the lamp post, the father and his son are 6 metres, 1.8 metres and 0.9 metres respectively, and the father is standing 2.1 metres away from the post, then how far ( in metres ) is the son standing from his father ?
Options: a. 0.9, b. 0.75, c. 0.6, d. 0.45, e. none of these

d