Which of These Statement Describes Blood Cells

Multiple Choice

Which of these statement describes blood cells

A) They all originate in red bone marrow.
B) Red bone marrow is the primary source of all blood cells except mast cells and macrophages.
C) Most types of leukocytes appear in equal amounts in the blood.
D) Erythrocytes are produced in red marrow, while leukocytes are produced primarily in lymph nodes.