The marks in an exam have a Normal distribution with mean 65 and standard deviation 15. A mark of 80 or above qualifies for an A grade. Adam, Bob and Cindy are three students writing this exam. Assume...

The marks in an exam have a Normal distribution with mean 65 and standard deviation 15. A mark of 80 or above qualifies for an A grade. Adam, Bob and Cindy are three students writing this exam. Assume that their marks are independent. What is the probability that that at least one of them will get an A grade?

(a) 0.60

(b) 0.15

(c) 0.50

(d) 0.40

(e) 0.05