Explanation:

Rice is the richest source of carbohydrates among the given options. It primarily contains starch, which is a complex carbohydrate. White rice has about 80% carbohydrates, making it a staple energy source in many diets worldwide.

Carbohydrate content in 100g of these grains:

• Rice → ~80g
• Maize (Corn) → ~74g
• Wheat → ~71g
• Jowar (Sorghum) → ~72g

Since rice has the highest carbohydrate content, the correct answer is (C) Rice.