A patient accidentally receives a unit of blood that is incompatible with their ABO blood type. Within minutes, the patient develops fever, chills, and signs of hemolysis. Which immunological mechanism best explains this reaction?

IgE-mediated mast cell degranulation causing systemic allergic inflammation

IgG or IgM antibodies binding to donor red blood cell antigens and activating complement-mediated lysis

T lymphocyte–mediated destruction of infected red blood cells

Immune complex deposition in small blood vessels causing complement activation