Which of the following grains is commonly used as food?

Rice is a staple grain that serves as a fundamental source of energy and nutrition for a large portion of the world's population. It can be prepared and consumed in various forms, such as steamed, fried, or as part of a dish, making it versatile and widely accepted in many cuisines. Its high carbohydrate content provides the necessary fuel for daily activities, and it can also be paired with numerous ingredients, enhancing its nutritional value and flavor profile. The popularity of rice across diverse cultures underscores its importance as a common food grain.

In contrast, while pasta and bread are also widely consumed, they are made from grains that have undergone processing or specific preparation methods. Onion, however, is not a grain but a vegetable, typically used as an ingredient to enhance flavor in cooking rather than a primary food source on its own. This distinction highlights rice's role as a fundamental grain-based food item.