A sample of 16 pvc valves for gas engines is randomly selected from a very large batch, and tested. Let X denote the number of valves out of the 16 selected that are found to be defective when tested. Valves are defective or non-defective independently. If the probability of a valve being defective is 0.02, find:
A. No valve is defective.
B. At the most one valve is defective.
C. At least one valve is defective.