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: Microbiology
Investigation of choice for detection of syphillis in a patient after 2 course of complete therapy - 
Select and explain. 
A. FTA ABS, B. VDRL, C. TPI, D. Dark ground microscopy
B: VDRL
Answer: B: VDRL 
Explanation: None