A urn contains 3 red and 5 black balls. Tom first withdraws a ball from the urn and Mary withdraws a ball from the urn without replacement. They keep withdrawing a ball alternately until a red ball is selected. Find the probability that Tom selects the red ball.
a) 3/8
b) 15/64
c) 31/56
d) 48/64
e) 34/56