Given below are two statements :
Statement 1 : The number of pairs among $\left[\mathrm{Al}_2 \mathrm{O}_3, \mathrm{Cr}_2 \mathrm{O}_3\right],\left[\mathrm{Cl}_2 \mathrm{O}_7, \mathrm{Mn}_2 \mathrm{O}_7\right],\left[\mathrm{Na}_2 \mathrm{O}, \mathrm{V}_2 \mathrm{O}_3\right]$ and $\left[\mathrm{CO}, \mathrm{N}_2 \mathrm{O}\right]$ that contain oxides of same nature (acidic, basic, neutral or amphoteric) is 4 .
Statement II : Among $\mathrm{Na}_2 \mathrm{O}, \mathrm{Al}_2 \mathrm{O}_3, \mathrm{CO}$ and $\mathrm{Cl}_2 \mathrm{O}_7$, the most basic and acidic oxides are $\mathrm{Na}_2 \mathrm{O}$ and $\mathrm{Cl}_2 \mathrm{O}_7$, respectively.
In the light of the above statements, choose the correct answer from the options given below :