The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Which material is the most difficult to remove from the patient's mouth?   (A) Metallic oxide paste   (B) Silicone impression material   (C) Reversible hydrocolloid   (D) Impression plaster
['(A) Metallic oxide paste <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Metallic oxide paste \n (B) Silicone impression material \n (C) Reversible hydrocolloid \n (D) Impression plaster <> possible answers', "  Which material is the most difficult to remove from the patient's mouth? <> context@"]