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: Skin
All are included in Amsler's criteria, EXCEPT: 
Select and explain. 
A. Vaginal pH <4.5, B. Positive amine test, C. Clue cells> 20% of total vaginal epithelial cells, D. Homogenous thin discharge
A: Vaginal pH <4.5
Answer: A: Vaginal pH <4.5 
Explanation: Amsler's criteria used for the diagnosis of bacterial vaginosis is based on clinical & lab indicators: Vaginal pH >4.5, alkaline Positive amine test Clue cells> 20% of total vaginal epithelial cells Homogenous thin discharge Scanty / absent lactobacilli 3 out of 5 criteria suggests this diagnosis Ref: Sexually transmitted infections, Bhushan Kumar, 2nd edition pg 673.