2.16 grams of Cu on reaction with `HNO_(3)` followed by ignition of the nitrate gave 2.7 gm of copper oxide. In another experiment 1.15 gm of copper oxide upon reduction with hydrogen gave 0.92 gm of copper. This data illustrate the law of
A. Multiple Proportions
B. Definite Proportions
C. Reciprocal proportions
D. Conservation of mass