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: one side of a rectangular field is 14 m and one of its diagonal is 17 m. find the area of the field.
Options: a. 134.4, b. 120, c. 150, d. 180, e. none
a

Problem: excluding stoppages, the average speed of a bus is 60 km / hr and including stoppages, the average speed of the bus is 40 km / hr. for how many minutes does the bus stop per hour ?
Options: a. 18 min, b. 17 min, c. 19 min, d. 20 min, e. 21 min
d

Problem: the standard deviation of a normal distribution of data is 2, and 3 standard deviations below the mean is greater than 48. what is a possible value for the mean of the distribution ?
Options: a. 46, b. 47, c. 48, d. 55, e. 50

d