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
Point source epidemic tends to -a) Continue over one incubation periodb) Produce multiple peaks in the epidemic curvec) Be explosived) Tail gradually 
Select and explain. 
A. bd, B. ac, C. bcd, D. da
B: ac
Answer: B: ac 
Explanation: None