What type of immunization will be administered to a preschool child in a modified bacteria immunization plan?

A vaccine is the correct answer because it is specifically designed to elicit an immune response by introducing a harmless part of the bacteria (or the bacteria itself in a weakened or killed form) to the body. This allows the child's immune system to recognize and combat pathogens, thereby providing immunity against future infections. In the context of a preschool child receiving immunizations, vaccines play a crucial role in preventing diseases common in early childhood.

The other terms refer to different types of immunological interventions. A toxoid is a modified toxin that has been detoxified but still elicits an immune response; while it is also administered in immunization schedules, it is not the broader category that encompasses all types of vaccines. An allergen is a substance that can cause an allergic reaction, which is unrelated to immunization against infectious diseases. An antitoxin is a substance used to neutralize toxins, typically in the context of treating toxin-mediated diseases rather than providing preventive immunity like a vaccine does.