The correct option is C CS2,CO2,SO2
In CS2 the ratio of the masses of C:S=12:64
In CO2 the ratio of the masses of C:O=12:32
So, the ratio of the masses of S:O combining with fixed mass of C=64:32=2:1
In SO2, the ratio of the masses of S:O=1:1
So,
21=2×(11)
Hence, this set follows law of reciprocal proportions.