input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Which one of the following is the role of barrier membrane in GTR?   (A) To help overall healing   (B) Prevention of epithelial migration   (C) To stop bleeding   (D) To prevent the underlying tissues from the infection
output: ['(B) Prevention of epithelial migration <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) To help overall healing  (B) Prevention of epithelial migration  (C) To stop bleeding  (D) To prevent the underlying tissues from the infection <> possible answers', '  Which one of the following is the role of barrier membrane in GTR? <> context']