Copper

The correct option is (A) : Alkanes

Step 1: Reaction of copper with air
When copper reacts with moist air (i.e., air containing water vapor and carbon dioxide), it undergoes a reaction to form basic copper carbonate. The reaction proceeds as follows: This product is known as basic copper carbonate, which is a greenish-blue compound, commonly referred to as patina when it forms on copper surfaces over time. Step 2: Analyzing the other options

• Copper carbonate (CuCO₃) – This is not the direct product of copper's reaction with moist air but forms under different conditions with excess CO₂.
• Copper oxide (CuO) – This forms when copper reacts with oxygen in dry air or oxygen-rich environments.
• Copper sulfate (CuSO₄) – This is formed when copper reacts with sulfuric acid, not with moist air.

Step 3: Conclusion
The correct compound formed is basic copper carbonate, hence the correct answer is: