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: Medicine
Which one of the following diseases has lowest incubation period 
Select and explain. 
A. Small pox, B. Diphtheria, C. Cholera, D. Dengue
C: Cholera
Answer: C: Cholera 
Explanation: Small pox - 7-14 days
Diphtheria - 2-6 days
Cholera - 1-2 days
Dengue - 3-10 days.