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
Considering the morphology of root and pulp canals, a root canal instrument should be placed in what direction to gain access to the Mesiofacial root of permanent maxillary first molar: 
Select and explain. 
A. From the mesiobuccal, B. From the distobuccal, C. From the mesiolingual, D. From the distolingual
D: From the distolingual
Answer: D: From the distolingual 
Explanation: None