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
25 year old labourer 3 years back presented with penile ulcer not treated. Later he presented with neurological symptoms for which he got treated. Test to monitor response to treatment is - 
Select and explain. 
A. VDRL, B. FTA-ABS, C. TPI, D. RPR
A: VDRL
Answer: A: VDRL 
Explanation: None