Answer: B

CBB gypsum, cassia, and oysters are heavy minerals, fossils, and shellfish, and are mostly placed on the lower layer of the bucket rack. Aconite and trichosanthes belong to the "Eighteen Antis" drugs that are incompatible and cannot be packed in one bucket or upper and lower medicine buckets. Green peel and dried tangerine peel are medicinal pairs that are often used together in the same prescription and are often placed in the same medicine bucket.