Answer:

Introduction:
In order to determine which of the given oxides react with both HCl and NaOH, we need to understand the properties of these oxides and their reactions with acids (HCl) and bases (NaOH).

Explanation:

Oxides and their reactions:
1. N2O5: Nitrogen pentoxide (N2O5) is an acidic oxide. It reacts with water to form nitric acid (HNO3). However, it does not react directly with HCl or NaOH. Therefore, option (a) is incorrect.
2. CaO: Calcium oxide (CaO) is a basic oxide. It reacts with water to form calcium hydroxide (Ca(OH)2), which is a base. It reacts with HCl to form calcium chloride (CaCl2) and with NaOH to form calcium hydroxide. Therefore, option (b) is incorrect.
3. CO2: Carbon dioxide (CO2) is a neutral oxide. It does not react directly with either HCl or NaOH. Therefore, option (c) is incorrect.
4. ZnO: Zinc oxide (ZnO) is an amphoteric oxide. It can react with both acids and bases.
- Reaction with HCl: ZnO reacts with HCl to form zinc chloride (ZnCl2) and water (H2O).
- Reaction with NaOH: ZnO reacts with NaOH to form sodium zincate [Na2Zn(OH)4].

Conclusion:
Based on the given information and the reactions of the oxides with HCl and NaOH, it can be concluded that zinc oxide (ZnO) is the only oxide among the given options that reacts with both HCl and NaOH. Therefore, the correct answer is option (d) ZnO.