dang probabilities!

The probability of each of three independent events is shown in the table below. What is the probability of A and C occurring, but not B? Event Probability of Occurrence A 25% B 15% C 42% A) 3.8%. B) 4.2%. C) 10.5%. D) 8.9%. I chose C, because I took .25 x .42 which was wrong. Why is this wrong?

because you need to multiply by the prob of B not occuring.

.25 * .85 * .42 = .08925 which is D

.25*.42*(1-.15) = D