Final answer:
The probability that at least one of the two persons in the married couple has high blood pressure is 0.28. The correct option is C.
Step-by-step explanation:
To find the probability that at least one of the two persons in the married couple has high blood pressure, we can find the probability of both of them not having high blood pressure and subtract it from 1.
Since the events of a male having high blood pressure and a female having high blood pressure are independent, the probability of neither of them having high blood pressure is (1-0.2)(1-0.1) = 0.72.
Therefore, the probability that at least one of them has high blood pressure is 1 - 0.72 = 0.28.