input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** During post preparation in distal canal of mandibular first molar, maximum chance of perforation is seen in:   (A) Lingual surface   (B) Distal surface   (C) Buccal surface   (D) Mesial surface
output: ['(D) Mesial surface <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Lingual surface  (B) Distal surface  (C) Buccal surface  (D) Mesial surface <> possible answers', '  During post preparation in distal canal of mandibular first molar, maximum chance of perforation is seen in: <> context']