The correct option is
A 3H2S+2K2CrO4+5H2SO4→Cr2(SO4)3+2K2SO4+8H2O+3SThe unbalanced redox equation is as follows:
H2S+K2CrO4+H2SO4→Cr2(SO4)3+K2SO4+S
Balance all atoms other than H and O.
H2S+2K2CrO4+5H2SO4→Cr2(SO4)3+2K2SO4+S
The oxidation number of Cr changes from 6 to 3. The change in the oxidation number of Cr is 3. The total change in the oxidation number for 2 Cr atoms is 6.
The oxidation number of S changes from -2 to 0. The change in the oxidation number of S is 2.
The increase in the oxidation number is balanced with a decrease in the oxidation number by multiplying H2S and S with 3.
3H2S+2K2CrO4+5H2SO4→Cr2(SO4)3+2K2SO4+3S
O atoms are balanced by adding 8 water molecules on RHS.
3H2S+2K2CrO4+5H2SO4→Cr2(SO4)3+2K2SO4+3S+8H2O
H atoms are balanced. This is the balanced chemical equation.