A patient develops a severe systemic allergic reaction (anaphylaxis) after receiving an injection of penicillin. Which type of hypersensitivity reaction is this, and what is the primary mediator involved?

✓ Correct Answer: Option D

Anaphylaxis is a classic Type I hypersensitivity reaction, mediated by IgE antibodies. Upon re-exposure, IgE bound to mast cells and basophils triggers their degranulation, releasing histamine and other potent inflammatory mediators.