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: a ladder 30 feet long is leaning against a wall that is perpendicular to level ground. the bottom of the ladder is 10 feet from the base of the wall. if the top of the ladder slips down 5 feet, how many feet will the bottom of the ladder slip ?
Options: a. 14, b. 15, c. 18.92, d. 19, e. 25
A:
c