**Core Concept**
Type II hypersensitivity, also known as cytotoxic hypersensitivity, occurs when antibodies bind to cell surface antigens, marking them for destruction. This can lead to the activation of complement, phagocytosis, or direct cell lysis.

**Why the Correct Answer is Right**
In the case of AIHA, antibodies against the RBCs (autoantibodies) are produced, which bind to the RBC surface. This binding leads to the activation of complement, resulting in the lysis of RBCs. The process involves the binding of IgG or IgM antibodies to RBC antigens, followed by complement activation and subsequent phagocytosis or lysis of the antibody-coated RBCs. This type of hypersensitivity reaction is mediated by antibodies, making it a classic example of Type II hypersensitivity.

**Why Each Wrong Option is Incorrect**
**Option A:** Type I hypersensitivity is an immediate allergic reaction mediated by IgE antibodies, leading to mast cell degranulation and histamine release, which is not relevant in this case.
**Option B:** Type III hypersensitivity involves the formation of antigen-antibody complexes that deposit in tissues, leading to inflammation and damage. While there is an immune component, the mechanism of RBC destruction in AIHA is distinct.
**Option C:** Type IV hypersensitivity is a cell-mediated reaction involving T cells, which is not the primary mechanism of RBC destruction in AIHA.

**Clinical Pearl / High-Yield Fact**
AIHA can be primary (idiopathic) or secondary to other conditions, such as infections, medications, or malignancies. It is essential to differentiate between warm and cold AIHA, as the latter is often associated with underlying conditions like mycoplasma infections or lymphoproliferative disorders.

**Correct Answer:** D.