The hemocytoblast (option B) are the parent cell for all formed elements of blood
Explanation:
All blood cells are originated from a common stem cell, which is called a pluripotent stem cell. It is capable of giving rise to any of the blood cells maintaining its existence through mitosis. By dividing pluripotent stem cells, new cells are originated, which become multipotent and differentiate into lymphoid (NK cell and the polymorphonuclear cell) or myeloid cells (megakaryocite); always respecting the original quantity.
