Which of the following is a common grade of beef found in restaurants and grocery stores?

The grade of beef commonly found in restaurants and grocery stores is Prime. This classification is designated by the U.S. Department of Agriculture (USDA) and indicates that it has a high level of marbling, which contributes to the flavor, tenderness, and juiciness of the meat. Prime beef typically comes from young, well-fed cattle and is often considered the highest quality of beef available.

In contrast, the other terms are not grades of beef but refer to cooking levels. Rare, medium, and well-done describe how thoroughly the meat is cooked, affecting the doneness but not the quality grade of the beef itself. Therefore, when determining the grades of beef available for purchase in stores and restaurants, Prime is recognized as a premium choice, making it the correct answer.