A physical property is a characteristic of a substance that can be observed or measured without changing its chemical composition. Among the options you provided, A being black in color is a physical property, as it describes a characteristic of the substance that can be observed without changing its identity.
The other options involve chemical changes or reactions:
- B neutralizing acids involves a chemical reaction.
- C burning with oxygen involves a combustion reaction, which changes the substance.
- D releasing SO2 gas also indicates a chemical change occurring.
So, the correct answer is A being black in color.