Any one of A, B, C could be the answer
Say the box contain White ball lebel as WR
" " Red " " " W
" " WhiteRed " " " R
If u put up a ball from box lebel R and the color of ball also Red
Then it must not be box of Red ball (As all boxes are mislabeled)
------->The box is filled up with WhiteRed
Next we have 2 boxes, and one box lebel White
---------> This box is filled up with Red balls (As it is also mislebeled and We already marked up WhiteRed Box)
----------> Last box must be filled up with White balls
Similarly in other approach too we get the correct result