Person or animal or object from which the infectious agent is transmitted–

Correct option is C

Sol. The source of infection is the immediate entity (person, animal, or object) from which an infectious agent is transmitted to a host. It may or may not be the reservoir. For example, a contaminated needle (source) may carry a virus that originated in a human (reservoir). Identifying and controlling the source is key in breaking the chain of infection.
Explanation of each option:
· (a) Agent – Refers to the microorganism (e.g., bacteria, virus, fungi) responsible for the disease. It’s not the person or object that transmits it.
· (b) Host – The individual who gets infected by the agent. The host is the recipient, not the transmitter of infection.
· (c) Source – Correct Answer. This is the direct transmitter of the pathogen, such as an infected patient, contaminated syringe, or animal.
· (d) Reservoir – The habitat in which the agent normally lives and multiplies (e.g., soil for tetanus). The source and reservoir can be the same or different.