A preventive measure that kills most bacteria to ensure a safe supply of milk is:

Correct option is A

Answer: (a) Pasteurization
Explanation: Pasteurization is the process of heating milk to a specific temperature for a set period to kill most harmful bacteria without significantly affecting the milk’s nutritional value. This method ensures the milk is safe for consumption by reducing the risk of diseases such as tuberculosis, brucellosis, and listeriosis.
Other Options Explained:
· (b) Clean dairy farm: Maintaining hygiene on a dairy farm is essential for preventing contamination, but it does not eliminate bacteria already present in milk.
· (c) Animal test: Testing animals helps identify diseases in livestock but does not directly ensure milk safety.
· (d) Milk inspection: While inspection helps in quality control, it does not eliminate bacteria.
Thus, the correct answer is pasteurization, as it directly kills bacteria and ensures a safe milk supply.