A bag contains an unknown number of blue and green marbles. If the probability of drawing a green marble and then a blue marble, P(G, then B), without replacement is equal to 1 over 4 • 1, how many green and blue marbles are in the bag at the beginning?
A. 1 green and 4 blue
B. 4 green and 1 blue
C. 1 green and 3 blue
D. 3 green and 1 blue