Urn A contains 5 red and 3 black marbles. Urn B contains 3 red marbles and 1 black marble. Urn C contains 4 red marbles and 2 black marbles. If an urn is selected at random and a marble is drawn,

a) Write the sample space of the experiment.

. b) Find the probability that the drawn marble is red.

c) Find the probability that the selected marble is drawn from the second urn given that it is red.