Recall the definition of amphoteric oxide

An amphoteric oxide is an oxide that reacts with both:

• acids, and
• bases

So we check each option accordingly.

Examine each oxide

A. $Na_2O$

• Sodium oxide is a basic oxide.
• It reacts with acids, but not with bases in the amphoteric sense.
• Hence, it is not amphoteric.

B. $SO_2$

• Sulfur dioxide is an oxide of a non-metal.
• Non-metal oxides are generally acidic oxides.
• Hence, $SO_2$ is not amphoteric.

C. $B_2O_3$

• Boron oxide is also generally classified as an acidic oxide.
• It reacts with bases to form borates.
• Hence, it is not amphoteric.

D. $ZnO$

• Zinc oxide reacts with acids: $ZnO + 2HCl \rightarrow ZnCl_2 + H_2O$
• It also reacts with bases: $ZnO + 2NaOH \rightarrow Na_2ZnO_2 + H_2O$
• Therefore, $ZnO$ is amphoteric.

Conclusion

The amphoteric oxide is: $\boxed{ZnO}$

Comparison with stored correct answer

• Derived answer: D
• Stored correct answer: D

They match.