What stem cell in the body divides to form all the blood cells in the process of blood cell formation?

Hematopoietic stem cell

Explanation:

The immature stem cell has the ability to form different types of blood cells in called blood stem cell.

The process of formation of different types of blood cell is called hematopoiesis of blood stem cell therefore the stem cell is known as the hematopoietic stem cell.

Hematopoietic stem cell forms the myeloid and lymphoid progenitors which on division forms a variety of blood cells. The blood stem cell is "multipotent" as it forms the variety of cells within one category like all the cells formed by the blood stem cell are blood cells.

Thus, Hematopoietic stem cell is the correct answer.