In a recent year, the total scores for a certain standardized test were normally distributed, with a mean of 500 and a standard deviation of 10.3. Answer parts (a)(d) below. (a) Find the probability that a randomly selected medical student who took the test had a total score that was less than 486. The probability that a randomly selected medical student who took the test had a total score that was less than 486 is (Round to four decimal places as needed.) (b) Find the probability that a randomly selected medical student who took the test had a total score that was between 500 and 513. The probability that a randomly selected medical student who took the test had a total score that was between 500 and 513 is (Round to four decimal places as needed.) (c) Find the probability that a randomly selected medical student who took the test had a total score that was more than 523. The probability that a randomly selected medical student who took the test had a total score that was more than 523 is (Round to four decimal places as needed.) (d) Identify any unusual events. Explain your reasoning. Choose the correct answer below. A. The event in part (c) is unusual because its probability is less than 0.05. B. The event in part (a) is unusual because its probability is less than 0.05. C. None of the events are unusual because all the probabilities are greater than 0.05. D. The events in parts (a) and (b) are unusual because their probabilities are less than 0.05.