Here are the solutions to the questions.
38. Probability
Step 1: Identify the given probability.
The probability that the dart will land in region D is P(D)=0.45.
Step 2: Calculate the probability that the dart will not land in region D.
The probability of an event not happening is 1 minus the probability of the event happening.
P(notD)=1−P(D)
P(notD)=1−0.45
P(notD)=0.55
The correct option is B.
The final answer is $\boxed{B. 0.