Final answer:
Roasts should not be left at room temperature for more than 2 hours after cooking and should be consumed within 3 to 4 days if stored properly in the refrigerator at 40°F or below.
Step-by-step explanation:
The question of how long a roast should be used after initial cooking concerns food safety, which is an important aspect of health education. According to food safety guidelines, cooked meats should not be left at room temperature for more than a total of 2 hours. However, if the question pertains to the maximum time a cooked roast should be stored in the refrigerator, then it should be consumed within 3 to 4 days when stored at 40°F (4°C) or below, which is safely under the USDA's recommended storage times. None of the provided options (a) 4 hours, (b) 6 hours, (c) 8 hours, and (d) 10 hours correspond accurately to food safety guidelines for usage after initial cooking. It is important to either consume or refrigerate the roast within 2 hours after cooking and then use it within 3 to 4 days.