input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Which of the following procedures can be used to treat an oro-antral fistula resulting from posterior surgery: (Or) Oro-antral fistula in maxillary 3rd molar region is best/commonly treated by   (A) Buccal mucoperiosteal flap   (B) Palatal mucoperiosteal flap   (C) Bridge flap   (D) Palatal island flap
output: ['(D) Palatal island flap <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Buccal mucoperiosteal flap  (B) Palatal mucoperiosteal flap  (C) Bridge flap  (D) Palatal island flap <> possible answers', '  Which of the following procedures can be used to treat an oro-antral fistula resulting from posterior surgery: (Or) Oro-antral fistula in maxillary 3rd molar region is best/commonly treated by <> context']