The correct option is
C All of the above
Mast cells are a type of white blood cells. It has granules which are rich in histamine and heparin. Histamine is a vasodilator which dilates post-capillary venules, activates the endothelium, and increases blood vessel permeability.
Heparin is an anticoagulant which is used to cure thrombosis. Serotonin is a vasoconstrictor which is secreted due to degranulation of mast cells. When the platelets bind to a clot, they release serotonin, where it serves as a vasoconstrictor and helps to regulate hemostasis and blood clotting.
So, the correct answer is option D.