The 50 songs on a smartphone consist of 15 that are rock, 20 that are jazz, and 15 that are country. Selections are played randomly and can be repeated. What is the probability of each of the following events?

a. The first two selections are both rock.
b. The first three selections are all jazz.
c. The first selection is jazz and the second is country.
d. The second selection is the same song as the first.