This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'Hard wax which is obtained by solvent extraction of certain types of lignite or brown coal is known as: \nSelect and explain. \nA. Montan wax, B. Carnuaba wax, C. Paraffin wax, D. Inlay wax', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Carnauba wax is often replaced in part by certain synthetic waxes that are compatible with paraffin wax. At least two waxes of this type can be used. One is a complex nitrogen derivative of the higher fatty acids and the other contains esters of acids derived from montan wax, a derivative hard wax that is obtained by solvent extraction of certain types of lignite or brown coal. Approximately a third of all montan wax produced is used in automobile polishing pastes.\nKey Concept\nMontan wax, also known as lignite wax or OP wax, is a hard wax obtained by solvent extraction of certain types of lignite or brown coal.\nPhillip’s 12th edition page 196', 'role': 'assistant'}]