Which of the following is a type of passive immunization?

Passive immunization involves the transfer of antibodies from one individual to another to provide temporary immunity. The injection of immunoglobulin is a prime example of this type of immunization. In this case, pre-formed antibodies are administered to the recipient, offering immediate, albeit short-term, protection against specific pathogens. The recipient's own immune system does not produce these antibodies; instead, they are derived from another source, often from donors who have recovered from an infection or who have received vaccines.

Breastfeeding is another method through which antibodies are transferred, as mothers can provide antibodies to their infants through breast milk; however, this is not typically classified as direct passive immunization but rather a natural way of providing some immunity during early life. Live attenuated vaccines and inactivated vaccines work by stimulating the recipient’s immune system to produce its own antibodies, which constitutes active immunization rather than passive. Therefore, the injection of immunoglobulin is the most accurate representation of passive immunization among the options provided.