**Core Concept**
Anaphylaxis is a severe, life-threatening allergic reaction that can occur within minutes of exposure to an allergen, such as a bee sting. This reaction is characterized by the release of histamine and other mediators from mast cells, leading to symptoms like generalized edema, sweating, flushing, tachycardia, and fever.

**Why the Correct Answer is Right**
The correct answer, **IgE mediated reaction**, is due to the role of IgE antibodies in triggering mast cell degranulation. When an individual is sensitized to an allergen, IgE antibodies bind to the allergen and also to high-affinity IgE receptors on the surface of mast cells. Upon subsequent exposure to the same allergen, the cross-linked IgE molecules on the mast cells trigger a cascade of signaling events, leading to the release of histamine and other preformed mediators from the mast cells. This results in the characteristic symptoms of anaphylaxis, including generalized edema, sweating, flushing, tachycardia, and fever.

**Why Each Wrong Option is Incorrect**
* **Option A:** T cell mediated cytotoxicity is a type of immune response that involves the direct killing of infected cells or foreign cells, and is not responsible for the symptoms seen in anaphylaxis.
* **Option C:** IgG mediated reaction is a type of antibody-mediated response that provides long-term immunity, but is not involved in the immediate, severe allergic reaction seen in anaphylaxis.
* **Option D:** IgA mediated hypersensitivity reaction is a type of immune response that is primarily involved in mucosal immunity, and is not responsible for the systemic symptoms seen in anaphylaxis.

**Clinical Pearl / High-Yield Fact**
Anaphylaxis is a medical emergency that requires prompt recognition and treatment. The classic symptoms of anaphylaxis include generalized edema, sweating, flushing, tachycardia, and fever, and treatment typically involves the administration of epinephrine via an EpiPen or other auto-injector device.

✓ Correct Answer: B. IgE mediated reaction