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: Surgery
Which of the following is the most difficult impaction of a third molar? 
Select and explain. 
A. Mesioangular impaction, B. Vertical impacted tooth, C. Partially impacted tooth, D. Distoangular impacted tooth
D: Distoangular impacted tooth
Answer: D: Distoangular impacted tooth 
Explanation: None