You are answering a USMLE-style medical question. Question: Candida is injected into the skin of a 38-year-old female patient. Forty-eight hours later, there is a 14 mm raised, slightly hardened area at the injection site. What type of hypersensitivity reaction has occurred and what cell type plays a role? Options: A) Type I hypersensitivty; eosinophils B) Type IV hypersensitivity; mast cells C) Type III hypersensitivity; CD4+ T cells D) Type IV hypersensitivity; CD4+ T cells Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.