Which of the following best defines a reservoir of infection?

A habitat — living or nonliving — where a pathogen normally lives, grows, and multiplies, serving as a continual source of infection.

A health-care intervention that interrupts transmission by separating infected hosts from susceptible individuals and by decontaminating environmental objects and surfaces.

An individual who has acquired immunity to a pathogen after vaccination and therefore no longer transmits the agent to others and cannot serve as a source of infection within the chain.

A temporary surface contaminated briefly with pathogens that cannot support long-term survival, such as a doorknob touched once and then cleaned immediately.