This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Other Key Definitions & Concepts, Subject name: Social & Preventive Medicine
Interval between Primary case and Secondary case known as:- 
Select and explain. 
A. Incubation period, B. Serial interval, C. Generation time, D. Case detection time
B: Serial interval
Answer: B: Serial interval 
Explanation: Serial Interval - Interval between primary case and secondary case. Incubation Period- Entry of organism till first sign / Symptom. Generation time - Interval between entry of organism till maximum infectivity of that person or case.