Vanadium can exhibit different oxidation states $\mathrm{V}^{2+}, \mathrm{V}^{3+}, \mathrm{V}^{4+}$, and $\mathrm{V}^{5+}$ in solution. The standard reduction potentials $\left(E^0\right)$ for the vanadium couples $\mathrm{V}^{3+} / \mathrm{V}^{2+}, \mathrm{V}^{4+} / \mathrm{V}^{3+}$, and $\mathrm{V}^{5+} / \mathrm{V}^{4+}$ are -0.25 volts, +0.337 volts and +1.00 volts, respectively. A solution of $\left(\mathrm{NH}_4\right)_3 \mathrm{VO}_4$ in dilute HCl is treated with tin ( $E^0$ for the couple $\mathrm{Sn}^{2+} / \mathrm{Sn}$ is -0.14 volts). The oxidation state of vanadium in the final solution is

• A

  $+5$
• B

  $+4$
• Correct answer
  C

  $+3$
• D

  $+2$

Hence, the correct answer is option: 'C'.