A student is taking 10 multiple choice questions on a quiz and each question has exactly five choices with only one correct answer. The student has not been doing any work in the course and does not know the material so he randomly guesses at all the answers. a.) What is the probability that he gets exactly 4 questions right? b.) What is the probability that he gets at most 3 questions right? c.) What is the probability that he gets all questions wrong?