A factory makes chocolate bars. Five boxes, labelled V, W, X, Y, Z, are each packed with 20 bars. Each of the bars in three of the boxes has a mass of 100 \mathrm{~g}. Each of the bars in the other two boxes has a mass of 90 \mathrm{~g}. One bar is taken from box V, two bars are taken from box W, four bars are taken from box X, eight bars are taken from box Y, and sixteen bars are taken from box Z. The total mass of these bars taken from the boxes is 2920 \mathrm{~g}. The boxes containing the 90 \mathrm{~g} bars are labelled
Answer Choices
A. V and W
B. W and Z
C. X and Y
D. V and Z
E. W and Y