The oxidation number of sulphur changes from?

In the reaction represented by the equation; 2FeCl3 + SO2 + 2H2O → 2FeCl2 + H2SO4 + 2HCl the oxidation number of sulphur changes from?

A. +2 to + 6
B. + 4 to + 6
C. 0 to + 6
D. – 2 to + 4
E. +2 to + 4

Correct Answer:

Option B – + 4 to + 6