Through April 30 of the 2009 filing season, 15.8% of all individual U.S. tax returns were prepared

Question:

Through April 30 of the 2009 filing season, 15.8% of all individual U.S. tax returns were prepared by H&R Block.
a. If two individuals are randomly selected from those filing tax returns during this period, what is the probability that both of their tax returns were prepared by H&R Block?
b. In part (a), what is the probability that neither return was prepared by H&R Block?
c. In part (a), what is the probability that exactly one of the two returns was prepared by H&R Block?