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
Prognosis is poor for furcation involvement of 
Select and explain. 
A. Maxillary 1st premolar, B. Maxillary 2nd molar, C. Mandibular 1st premolar, D. Maxillary 2nd premolar
A: Maxillary 1st premolar
Answer: A: Maxillary 1st premolar 
Explanation: None