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
Most asymmetrical premolar is 
Select and explain. 
A. Upper 1st premolar, B. Lower 1st premolar, C. Upper 2nd premolar, D. Lower 2nd premolar
A: Upper 1st premolar
Answer: A: Upper 1st premolar 
Explanation: None