Answer: Option (b) is the correct answer.
Step-by-step explanation:
When a teaspoon of salt is dissolved in water then it will completely dissociate into ions forming a homogeneous solution.
This is because particles of salt will evenly distribute into ions in the water.
This is a physical change as salt has dissociated into its ions and it has not chemically combined to the water molecules.
Hence, both salt and water will retain their chemical; properties.
Thus, we can conclude that in the given situation it’s a physical change because the water and the salt kept their original properties.