input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Bacteria free zone of dentinal caries is   (A) a)Zone of decomposed dentin   (B) Zone of bacterial invasion   (C) Zone of decalcification   (D) Zone of dentinal sclerosis
output: ['(D) Zone of dentinal sclerosis <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) a)Zone of decomposed dentin  (B) Zone of bacterial invasion  (C) Zone of decalcification  (D) Zone of dentinal sclerosis <> possible answers', '  Bacteria free zone of dentinal caries is <> context']