Concept: This question tests your knowledge of common plant species, their botanical names, and their economic importance or uses, particularly in the context of food sources.

Why (B) is correct: Manihot utilissima is the botanical name for tapioca or cassava. Its root tubers are indeed a significant source of carbohydrates and are widely consumed, especially in regions like Kerala, India, where it's a staple food.

Why other options are wrong:

• (A) Oryza sativa - rich source of protein: Oryza sativa is rice, which is primarily a rich source of carbohydrates, not protein.
• (C) Ricinus communis - important edible cereal: Ricinus communis is castor bean, known for castor oil, which is not an edible cereal. Cereals are grasses cultivated for their edible grain.
• (D) Hibiscus esculentus - flowers eaten throughout the country: Hibiscus esculentus is okra (lady's finger), and it's the fruit (pod) that is eaten, not the flowers.

NEET Tip / Mnemonic: When studying plant names, try to associate the scientific name with its common name and primary use. For example, 'Oryza' for rice, 'Manihot' for tapioca/cassava, 'Ricinus' for castor, 'Hibiscus' for okra/lady's finger.

Correct Answer: (B)