What Is the Mechanism in Type IV Hypersensitivity Reactions

Multiple Choice

What is the mechanism in type IV hypersensitivity reactions?

A) Antibodies coat mast cells by binding to receptors that signal its degranulation followed by discharge of preformed mediators.
B) Antibodies bind to soluble antigens that were released into body fluids and the immune complexes are deposited in the tissues.
C) Cytotoxic T lymphocytes or lymphokine-producing Th1 cells attack and destroy cellular targets directly.
D) Antibodies bind to the antigen on the cell surface.