All Human Blood Can Be Typed as Either O, A

All human blood can be typed as either O, A, B, or AB. The distribution of the types varies a bit with race. Choose an African American person at random. Here are the approximate probabilities that the person you choose will have blood type O, B, or AB:
?
$$\begin{array} { | l | l | l | l | l | } \hline \text { Blood type } & \text { O } & \text { A } & \text { B } & \text { AB } \\\hline \text { Probability } & 0.50 & ? & 0.20 & 0.05 \\\hline\end{array}$$ What is the probability that the person chosen has a blood type other than O?

A) 0.25
B) 0.50
C) 0.75
D) 1.00