Statement-by-statement check: Assertion (A) is a factual claim, cover cropping is indeed a standard, widely recommended practice in organic systems.
Reason (R) lists three concrete mechanisms, soil health improvement, weed suppression through ground cover, and biodiversity enhancement through added plant diversity, that are precisely why organic growers adopt cover crops, since organic systems avoid synthetic weedicides and fertilisers and instead rely on such biological tools.
Because every mechanism in (R) is a direct cause of why cover cropping fits organic principles, (R) does not merely sit alongside (A), it logically accounts for it. This makes the correct option the one where both statements are true and (R) explains (A).