A well-calibrated scale reads zero when nothing is placed on it. When a deflated balloon is placed on the scale, it reads m g. When a non-airtight box is placed on the scale, it reads M g, where M>m. The balloon is inflated with helium, so that it floats upward in air. The balloon is placed in the box, and the box is placed on the scale. If the scale reads W, which of the following is true?
Answer Choices
A. W \leq(M-m) g
B. (M-m) g<W<(M+m) g
C. W=(M+m) g
D. W>(M+m) g
E. None of the above are necessarily true.