**Core Concept**
Active immunization, achieved through vaccination, induces a specific and long-lasting type of immunity known as adaptive or acquired immunity. This type of immunity involves the activation and proliferation of immune cells, such as B cells and T cells, which recognize and respond to specific pathogens, thereby providing long-term protection against future infections.

**Why the Correct Answer is Right**
Vaccination stimulates the production of antibodies, which are proteins produced by B cells that recognize and bind to specific pathogens, neutralizing or removing them from the body. Additionally, vaccination activates T cells, which recognize and eliminate infected cells. This immune response is specific to the vaccine antigen and can provide long-term protection against future infections. The type of immunity conferred by vaccination is known as adaptive or acquired immunity.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because innate immunity refers to the non-specific defense mechanisms that provide immediate protection against infection, such as the physical barrier of skin and mucous membranes, and the inflammatory response.

**Option B:** This option is incorrect because passive immunity refers to the transfer of pre-formed antibodies from an immune individual to a non-immune individual, such as through breast milk or immunoglobulin injections.

**Option C:** This option is incorrect because hypersensitivity reactions refer to abnormal immune responses that can lead to tissue damage or disease, such as allergic reactions or autoimmune disorders.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that vaccination not only protects the individual who receives the vaccine but also helps to prevent the spread of infectious diseases in the community, thereby protecting vulnerable populations such as the elderly, young children, and those with compromised immune systems.

**Correct Answer: A. Adaptive or acquired immunity**