<u>Answer: </u>The correct answer is Option C.
<u>Explanation:</u>
Reverse reaction is defined as the chemical reaction in which the reactants forming products at first, react together to give back the reactants.
Forward reaction is given by the equation:

Now, the reverse reaction for this will be:

- According to the question:
Sulfur dioxide and oxygen are reacting together to form sulfur trioxide. The forward reaction for this will be:

The reverse reaction for this will be:

Hence, the correct answer is Option C.