The correct option is Ragi.
Explanation
Millets, often referred to as "coarse grains" or "nutri-cereals," are recognized for their superior nutritional profile compared to staple cereals like rice and wheat. They are particularly dense in minerals, vitamins, and dietary fiber.
Nutritional Profile Analysis:
- Ragi (Finger Millet): It is a crop of dry regions and is exceptionally rich in iron, calcium, other micronutrients, and roughage. It contains the highest amount of calcium (approximately 344 mg per 100g) among all cereals and millets.
- Bajra (Pearl Millet): While Bajra is rich in iron and energy, it does not possess the high calcium content characteristic of Ragi.
- Maize: Used as both food and fodder, maize is a significant source of carbohydrates but does not match the mineral density (specifically calcium and iron) of Ragi.
- Rice: This is a staple food crop primarily consisting of starch (carbohydrates) and is relatively low in micronutrients and roughage unless fortified.
Key Takeaway: Ragi is distinct among cereals for having the highest calcium content and is explicitly noted in agricultural geography for being rich in iron, micronutrients, and roughage.