Which of the following is NOT a mode of bacterial transmission?

Antibody production is indeed not a mode of bacterial transmission. Bacterial transmission refers to the ways in which bacteria spread from one host to another or from an environment into a host. Transmission modes commonly include respiratory droplets, where bacteria are expelled through coughing or sneezing; contaminated water, which involves ingestion of bacteria present in water sources; and direct contact, which can occur through physical touch or contact with contaminated surfaces.

In contrast, antibody production is a part of the immune response to infection. When the body encounters bacteria, it produces antibodies to identify and neutralize these pathogens. Rather than being a means by which bacteria are transmitted, antibody production is a defensive mechanism employed by the immune system to eliminate or prevent bacterial infections. This fundamental difference clarifies why antibody production is not considered a mode of bacterial transmission.