Answer: Option D
Explanation: There are certain safety guidelines that should be maintained while preparing and storing food. These guidelines helps to keep the food healthy and prevents from spoilage.
One of the safety guidelines states that food should not be kept outside until it cools down and then putting it inside the refrigerator. The bacteria can grow in the food within two hours unless it is refrigerated.
So, it should be kept inside the refrigerator before two hours.