Steven is an incoming college freshman and is selecting his courses for the semester. He estimates that the probability he takes Calculus is 0.7 and the probability he takes Biology is 0.1. Due to scheduling conflicts, he will not take both of these classes.

(a) What is the probability that he does not take Calculus?

(b) What is the probability that he takes at least one of these classes?

(c) What is the probability that he does not take either of these two classes?