4. An insurance company believes that people can be divided into two classes - those are accident-prone and those are not. Their statistics show that an accident-prone person will have an accident at some time within a fixed I-year period with probability 0.5, whereas this probability decreases to 0.4 for a non-accident-prone person. If we assume that 40% of the pcpulation is accident-prone, what is the probability that a new policy holder will have an accident within a year of purchasing this policy? (A)0.44 (B) 0.45 (C) 0.46 (D) 0.47