According to tables provided by the U.S. National Center for Health Statistics in Vital Statistics of the United States, there is roughly an 80% chance that a person aged 20 will be alive at age 65. Suppose that three people aged 20 are selected at random. Find the probability that the number alive at age 65 will be
a.exactly two.
b.at most one.
c.at least one.
d.Determine the probability distribution of the number alive at age 65.