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: Pathology
For primary herpes simplex, the diagnosis is made by which gene 
Select and explain. 
A. Culture with giernsa stain, B. Culture with wright strain, C. Routine cytology, D. Flourescent stain for cytology
D: Flourescent stain for cytology
Answer: D: Flourescent stain for cytology 
Explanation: None