This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intestinal Infections, Worm Infestations, Subject name: Social & Preventive Medicine
Which of the following disease has incubation period< 1week? 
Select and explain. 
A. Cholera, B. Kala-azar, C. Filariasis, D. Measles
A: Cholera
Answer: A: Cholera 
Explanation: Incubation period of cholera: 1-2 days. Incubation period of kala azar: 1-4 months. Incubation period of filariasis: 8-16 months. Incubation period of measles: 10-14 days.