The correct answer is C) Brine. Brine, which is a concentrated salt solution, is suitable for use as a secondary refrigerant. Secondary refrigerants are used to transfer heat from the primary refrigerant to the area that needs cooling. Brine is an effective secondary refrigerant because it can withstand low temperatures without freezing and has a high specific heat capacity, allowing it to efficiently absorb and transfer heat. The other options are not suitable for use as secondary refrigerants. Carbon dioxide (A) is a primary refrigerant, not a secondary one. Methyl alcohol (B) is a flammable and toxic substance, making it unsuitable for use in refrigeration systems. Cuprous chloride (D) is a chemical compound that is not commonly used as a refrigerant.