many balls must

[sanju09]

A box contains 20 balls, of which 4 are white, 7 are black and 9 are red. At least how many balls must one remove in a single pick to get 4 balls of the same color?
(A) 9
(B) 10
(C) 13
(D) 14
(E) 15

[harsh.champ]

A box contains 20 balls, of which 4 are white, 7 are black and 9 are red. At least how many balls must one remove in a single pick to get 4 balls of the same color?
(A) 9
(B) 10
(C) 13
(D) 14
(E) 15

3,3,3 from each color.
The 10th ball would correspond to any of the 3 colors
Hence,B should be the answer.