Two marbles are drawn at random and without replacement from a box containing 2 red, 3 green, and 4 blue marbles.

Let's define the following events:

A = {two red marbles are drawn}
B = {two green marbles are drawn}
C = {two blue marbles are drawn}
D = two marbles of the same color are drawn}

Find the probabilities of the following events:

(a) P(A), P(B), P(C), and P(D).

(b) P(A|D).