Final answer:
Leftovers should be consumed within three to four days when stored at or below 4 degrees C (40 degrees F). It is important to maintain proper refrigerator temperatures to prevent bacterial growth and use a thermometer to ensure food safety.
Step-by-step explanation:
To ensure safety, leftovers that have been properly wrapped and refrigerated should be eaten within three to four days. While the question provides specific choices, the general guideline from food safety authorities is that leftovers can be kept in the fridge for this duration before they should be discarded to ensure they are safe to consume.
It is crucial to keep the temperature of the refrigerator at or below 4 degrees C (40 degrees F) to prevent bacterial growth. If the fridge temperature rises above this point for more than two hours, the safety of the food could be compromised. In such cases, or if food has been left at room temperature for too long, it should not be consumed even if adequately reheated, since bacteria that cause foodborne illnesses could have multiplied to dangerous levels. Always ensure you're using a thermometer to check food temperatures, both in the refrigerator and during cooking.