Which among the following is NOT one of the four types of immunity?

• A. Natural
• B. Artificial
• C. Active
• D. Static

Answer: (D)

The immune system encompasses various types of immunity that protect the body from pathogens and diseases. Among these, natural immunity is typically acquired through exposure to pathogens in everyday life, while artificial immunity is gained through medical interventions such as vaccinations. Active immunity arises when the body produces its own antibodies in response to an antigen, either through natural infection or vaccination.

Static immunity, however, is not classified as a type of immunity. The concept of "static" does not correspond to any recognized category within immunology that describes how the body responds to infections or foreign substances. Thus, it is correct to identify it as not being part of the established four types of immunity, which generally include natural, artificial, active, and passive immunities.