Final answer:
Monocytes originate from myeloid stem cells, specifically from the common myeloid progenitor (CMP) in the bone marrow.
Step-by-step explanation:
Monocytes are derived from myeloid stem cells. Hematopoietic stem cells in the red bone marrow differentiate into either myeloid or lymphoid stem cells. Myeloid stem cells specifically give rise to several types of blood cells, including erythrocytes, megakaryocytes that produce platelets, and a myeloblast lineage that further differentiates into monocytes and three types of granular leukocytes (neutrophils, eosinophils, and basophils). Therefore, the correct answer to which stem cells monocytes are derived from is CMP, or common myeloid progenitor.