Notice that the graph plots points that as we move along the horizontal axis, go down in value. The Horizontal axis is most likely representing the time elapsed in each description.
Then, we DISCARD the first answer, since the cost of muffins don't go down as time goes by.
Answer b is a POSSIBLE answer, since the distance as the train approaches the station, is reducing (going down in value) as time goes by.
Answer C is not a good answer (we discard it) since after paying a roll each day, the number of quarters in each roll doesn't go down because we pay with the entire roll.
Answer d is also discarded, since the distance covered by the runner, should be going UP (increasing) as time goes by
Therefore, answer b) is the selected answer.
