Answer: Option (3) is the correct answer.
Step-by-step explanation:
A property which does not bring any change in the chemical composition of a substance is known as physical property.
For example, shape, size, mass, volume, density, boiling point, melting point etc of a substance are all physical properties.
Whereas a property which changes the chemical composition of a substance is known as chemical property.
For example, precipitation, reactivity, toxicity etc are chemical property.
Thus, we can conclude that out of the given options reactivity is an example of a chemical property.