**Core Concept:** Type-2 hypersensitivity is a part of the hypersensitivity reactions classified by the World Health Organization (WHO) into six categories based on the immune response and time course. Type-2 reactions involve the release of inflammatory mediators from activated mast cells and eosinophils, leading to tissue damage. Antibodies play a significant role in these reactions, particularly Immunoglobulin E (IgE).

**Why the Correct Answer is Right:** The correct answer is Immunoglobulin E (IgE) because it is the primary antibody involved in type-2 hypersensitivity reactions. IgE binds to the high-affinity receptors on the surface of mast cells and basophils, leading to the release of inflammatory mediators upon antigen re-exposure, which results in the typical clinical manifestations of type-2 reactions.

**Why Each Wrong Option is Incorrect:**

A. Immunoglobulin G (IgG) is involved in type-4 hypersensitivity reactions (delayed hypersensitivity), not type-2 reactions.
B. Immunoglobulin M (IgM) is involved in the primary immune response and does not play a significant role in type-2 hypersensitivity reactions.
C. Immunoglobulin A (IgA) is involved in the mucosal immune response and does not directly contribute to the type-2 hypersensitivity reactions.
D. Immunoglobulin D (IgD) is a rare immunoglobulin that does not play a significant role in type-2 hypersensitivity reactions.

**Clinical Pearl:** Understanding the role of various immunoglobulins in different types of hypersensitivity reactions is essential for medical students and practicing physicians alike. This knowledge helps in diagnosing and managing patients with allergic diseases such as asthma, atopic dermatitis, and eosinophilic gastrointestinal disorders.