The probability that a person in the United States has type B​+ blood is 13​%.
Four unrelated people in the United States are selected at random.
Complete parts​ (a) through​(d).

(a) Find the probability that all four have type B​+ blood.The probability that all four have type B​+ blood is?
​(Round to six decimal places as​ needed.)
​(b) Find the probability that none of the four have type B​+ blood.The probability that none of the four have type B​+ blood is?
​(Round to three decimal places as​ needed.)
​(c) Find the probability that at least one of the four has type B​+ blood.The probability that at least one of the four has type B​+ blood is?
​(Round to three decimal places as​ needed.)
​(d) Which of the events can be considered​ unusual? Explain. Select all that apply.
A.None of these events are unusualNone of these events are unusual.
B.The event in part​ (a) is unusual because its probability is less than or equal to 0.05.
C.The event in part​ (b) is unusual because its probability is less than or equal to 0.05.
D.The event in part​ (c) is unusual because its probability is less than or equal to 0.05.