Point out the incorrect reaction from the following.

Options

1. A$2 \mathrm{Na}_2 \mathrm{CrO}_4+\mathrm{H}^{+} \longrightarrow \mathrm{Na}_2 \mathrm{Cr}_2 \mathrm{O}_7+2 \mathrm{Na}^{+}+\mathrm{H}_2 \mathrm{O}$
2. B$4 \mathrm{MnO}_2+4 \mathrm{KOH}+\mathrm{O}_2 \longrightarrow 4 \mathrm{KMnO}_4+2 \mathrm{H}_2 \mathrm{O}$
3. C$$\begin{aligned} 2 \mathrm{MnO}_4^{-}+5 \mathrm{C}_2 \mathrm{O}_4^{2-}+16 \mathrm{H}^{+} \longrightarrow \\ 2 \mathrm{Mn}^{2+}+10 \mathrm{CO}_2+8 \mathrm{H}_2 \mathrm{O}\end{aligned}$$
4. D