How Are Platelets Released into Peripheral Circulation from the Bone

How are platelets released into peripheral circulation from the bone marrow?

A) Mature platelets squeeze between sinusoid endothelial cells.
B) Megakaryocyte cytoplasmic fragments extend through the endothelial cells, lining the sinusoids, into blood and then shed platelets.
C) Platelets adhere to white cells and exit with them.
D) Megakaryocytes exit the marrow with white cells, and then platelets fragment off once they reach the blood.