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: Social & Preventive Medicine
Incubation period of chancroid is 
Select and explain. 
A. Less than 7 days, B. 10-15 days, C. 2-3 weeks, D. 3-4 weeks
A: Less than 7 days
Answer: A: Less than 7 days 
Explanation: None