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
The person, animal, object or substance from which an infectious substance passes or is disseminated by host is called - 
Select and explain. 
A. Reservoir, B. Source, C. Carrier, D. Homologous reservoir
B: Source
Answer: B: Source 
Explanation: None