Final answer:
The probability of two mutually exclusive events occurring together is 0, therefore the answer to the question about P(HD) is B. 0.
Step-by-step explanation:
The question asks about the probability of the intersection of two mutually exclusive events, which by definition, cannot happen at the same time. If events H and D are mutually exclusive, the probability of H and D occurring together, denoted as P(HD), is 0. This is because if one event occurs, the other cannot possibly occur. In mathematical terms, P(HD) for mutually exclusive events is always 0. Therefore, the answer to the question is B. 0.