Which of the following statements is true?

Options

1. A$\mathrm{H}_3 \mathrm{PO}_3$ is a stronger acid than $\mathrm{H}_2 \mathrm{SO}_3$
2. BIn aqueous medium $\mathrm{HF}$ is a stronger acid than $\mathrm{HCl}$
3. C$\mathrm{HClO}_4$ is a weaker acid than $\mathrm{HClO}_3$
4. D$\mathrm{HNO}_3$ is a stronger acid than $\mathrm{HNO}_2$