The correct answer is:
A. rate of rusting.
Explanation:
1. Physical properties of matter are characteristics that can be observed or measured without changing the identity of the substance.
2. The rate of rusting is a chemical property because it involves the interaction of the metal with oxygen in the environment, leading to the formation of rust, which changes the identity of the substance.
3. Density, freezing point, and melting point are examples of physical properties because they can be measured or observed without altering the substance's chemical composition.
