Which of the following statements best captures an aspect of the process of hematopoiesis?
A. Colony-stimulating factors (CSFs) produce cytokines that activate progenitor cells.
B. Various subtypes of pluripotent stem cells eventually differentiate into the cellular components of blood.
C. Progenitor cells differentiate into precursor cells.
D. Self-replicating precursor cells differentiate into specific CSFs.