Q. Histamine is released by which of these cells ?

A) Macrophages
B) Lymphocytes
C) Mast cells
D) Basophils

... Answer is C). Mast cells

A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin. Although best known for their role in allergy and anaphylaxis, mast cells play an important protective role as well, being intimately involved in wound healing and defense against pathogens.