Passive immunization occurs when:

• A. Administer protective antibodies to an individual
• B. Administration of antigens so patient actively mounts a protective immune response
• C. Immunologic defenses developed by person's own body
• D. Immunity obtained from mother via breastfeeding

Answer: (A)

Passive immunization means giving someone ready-made antibodies to provide immediate protection, without requiring the person’s own immune system to respond. This is an external supply of antibodies, so protection appears right away but is temporary.

This differs from activating the person’s own defenses: active immunization involves introducing antigens (like vaccines) to stimulate the body's immune response and produce antibodies and memory. When immunity is developed by the person’s own body, that’s active immunity.

While maternal antibodies transferred through breastfeeding are a form of passive immunity, that’s natural passive protection rather than a deliberate immunization procedure. The clinical idea of passive immunization is the direct administration of protective antibodies.

So, giving protective antibodies to a person best captures the concept.