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
Normal level of PSA is 
Select and explain. 
A. < 4 ng/ml, B. 4-7 ng/ml, C. 4 - 11ng/ml, D. > 11 ng/ml
A: < 4 ng/ml
Answer: A: < 4 ng/ml 
Explanation: In BPH , prostatitis and cancer is PSA is raised.