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: the speed of a railway engine is 74 km per hour when no compartment is attached, and the reduction in speed is directly proportional to the square root of the number of compartments attached. if the speed of the train carried by this engine is 24 km per hour when 9 compartments are attached, the maximum number of compartments that can be carried by the engine is :
Options: a. 49, b. 18, c. 16, d. 17, e. 19
A:
e