Which of the following is NOT correctly matched?

The correct answer is D. Pasteurisation is a mild heat treatment, named after Louis Pasteur, used to kill pathogens and spoilage organisms in liquids such as milk, fruit juices and beer, without full sterilisation. It is not a process associated with tea, so this pairing is the mismatch.

Check the other three. Desalination removes dissolved salts from sea water, typically by reverse osmosis or multi-stage flash distillation, so A is correct. Reverse osmosis forces water through a semi-permeable membrane and is widely used to produce potable water from brackish or sea water, so B is correct. Denaturation is the loss of a protein's three-dimensional structure caused by heat, pH change or chemicals, so C is correct.

• Core concept: match a process to its real application, not to a loosely related material.
• Syllabus link: water treatment and food preservation fall under Science and Technology and Environment; for Mains, desalination and reverse osmosis connect to water security and access to safe drinking water.

Trap: aspirants see heating and assume every hot beverage is pasteurised. Tea is brewed with boiling water, which is a different process from pasteurisation.