The following are multiple choice questions (with answers) about medical knowledge.   **Question:** The upper denture falls when the patient opens his mouth wide. This is due to:   (A) Thick labial flange   (B) Over-extended borders   (C) Thick disto-buccal flange   (D) Poor peripheral seal
['(C) Thick disto-buccal flange <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Thick labial flange \n (B) Over-extended borders \n (C) Thick disto-buccal flange \n (D) Poor peripheral seal <> possible answers', '  The upper denture falls when the patient opens his\nmouth wide. This is due to: <> context@']