Angie has a jar that contains 2 red marbles, 2 blue marbles, and no other marbles. she randomly draws 2 marbles from the jar. if the marbles are the same colour, she discards one and puts the other back into the jar. if the marbles are different colours, she discards the red marble and puts the blue marble back into the jar. she repeats this process a total of three times. what is the probability that the remaining marble is red?
(a) 1/2 (b) 1/4 (c) 2/3 (d) 1/3 (e) 0