Teacher: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.
Teacher: Now, understand the problem? Solve this instance: Problem: in a certain alphabet, 9 letters contain a dot and a straight line. 24 letters contain a straight line but do not contain a dot. if that alphabet has 40 letters, all of which contain either a dot or a straight line or both, how many letters contain a dot but do not contain a straight line ?
Options: a. 7, b. 8, c. 14, d. 20, e. 28
Student:
a