Final answer:
The correct temperature to cool soup properly within four hours and avoid the 'danger zone' for bacterial growth is 20°C.
Step-by-step explanation:
The question is regarding the safe temperature that soup must reach within four hours to avoid bacterial growth, which is a matter of food safety and health. According to food safety guidelines, perishable foods should not be left at a temperature between 4°C (40°F) and 60°C (140°F) for more than two hours. This temperature range is known as the 'danger zone' where bacteria can grow rapidly. To cool soup properly and minimize the risk of foodborne illness, it should be brought down to a temperature below the danger zone as quickly as possible.
Therefore, the correct answer to the question, 'What temperature must the soup reach in the next four hours to be cooled properly?', is c) 20°C, which is well below the danger zone and ensures that the soup is stored safely to prevent bacterial growth. This quick cooling process is essential for maintaining food at a safe temperature until it is served or stored.