Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour?

In an oxidizing reaction, the oxidation state of the central atom of the acid ($\text{S}$ in ${\text{H}}_2{\text{SO}}_4$) must decrease.In B, C, and D, $\text{S}$ ($+6$) is reduced to ${\text{SO}}_2$ ($+4$).In A (${\text{CaF}}_2+{\text{H}}_2{\text{SO}}_4\to {\text{CaSO}}_4+2\text{HF}$), the oxidation states of all atoms remain the same ($\text{Ca}$ is $+2$, $\text{F}$ is $-1$, $\text{S}$ is $+6$). This is a double displacement (acid-salt) reaction, not a redox reaction.