A television manufacturing company performs quality assurance tests of its products before shipping them to the market. If the company chooses a random sample of 15 sets for the test, and assuming that based on previous data the company has a 6% failure rate for the newly manufactured sets, what is the probability that: a) none of the TV sets are defective. b) exactly one of the TV sets is defective. c) two or fewer of the TV sets are defective