Which of the following changes is NOT a chemical change? 

The information concerning physical and chemical changes is provided by this inquiry. Chemical and physical changes affect the entire compound and entail chemical processes, whilst physical changes affect the compounds' appearance.

Water boiling is a physical transformation rather than a chemical one.
The substances' appearances alter as a result of physical changes. Physical attributes, such as size, form, and so on, alter as a result of physical changes. It often experiences a brief alteration. There is no creation of new substances during physical changes. Because physical changes are reversible in nature, parent molecules may always be obtained. Physical changes do not entail the production of energy.

Wax melting, water freezing or boiling, ice melting, glass shattering, wood cutting, paper shredding, sand combining with water, can smashing, dry ice sublimation, and other physical changes are examples of physical transformations.
The appearance of the substances is unaffected by chemical changes. Chemical reaction is another name for a chemical change. It often experiences a lasting alteration. New substances are created when chemicals are changed. Because chemical changes are inherent in nature, parent molecules can never be restored. Physical changes include the production of energy. During chemical reactions, energy is both emitted and absorbed.

Examples of chemical changes are changing colors, precipitation, emission of gases, emission of odor, formation of new compounds during chemical reactions, change in oxidation state and so forth.

Therefore, option, ‘C. Boiling of water’ is correct.