Sulfur dioxide is an atmospheric pollutant responsible for acid rain. One reaction in this sequence is the conversion of sulfur dioxide into sulfur trioxide by oxidation. This oxidation occurs in a two-stage reaction that involves oxygen and nitrogen monoxide, NO. $\text{NO} + \frac{1}{2}\text{O}_2 \rightarrow \text{NO}_2$ $\text{NO}_2 + \text{SO}_2 \rightarrow \text{SO}_3 + \text{NO}$ Which of the following statements are correct?
- A1, 2 and 3 are correct
- B1 and 2 only are correct
- C2 and 3 only are correct
- D1 only is correct