Based on the given scenario above, the correct answer would be option A. So when a farmer planted legumes and cabbage in the same field that is devoid of fertilizers and seen that the yield from this field is better than the cabbage planted in another field without legumes, this is because of the nitrogen-fixing bacteria that is present in the roots of legumes aid enrichment of nitrogen in the soil. This bacteria is called Rhizobium. Hope this helps.
