Given the task definition and input, reply with output. 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: - - - - - - - - - - - - - - - - yes - - - - - - - - - no - - - - unsure subject m - - - - 500 - - - - - - - - 200 - - - - - 100 subject r - - - - 400 - - - - - - - - 100 - - - - - 300 a total of 800 students were asked whether they found two subjects, m and r, interesting. each answer was either yes or no or unsure, and the numbers of students who gave these answers are listed in the table above. if 140 students answered yes only for subject m, how many of the students did not answer yes for either subject ?
Options: a. 100, b. 260, c. 360, d. 400, e. 500
b