19) In a box there are four bags: the first bag contains 4 white balls and 3 black balls, the second 2 white balls and 4 black balls, the third 6 white balls and 9 black balls, the fourth 5 white balls and 10 black balls. A bag is drawn at random, and from this, a ball is drawn at random. Knowing that a white ball has been drawn, which bag is it most likely that was chosen?
(A) The first
(B) the second
(C) the third
(D) the fourth

(E) all bags have the same probability of being chosen.