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
Oral ulcers that are painless are associated with 
Select and explain. 
A. Secondary herpes, B. Primary syphilis, C. Tuberculosis, D. Primary herpes
B: Primary syphilis
Answer: B: Primary syphilis 
Explanation: None