Step 1: Recall the erythropoiesis stages.
Erythropoiesis is the bone marrow process of red blood cell (RBC) production, commencing with a proerythroblast and concluding with a mature RBC.
Step 2: First stage – Proerythroblast.
The proerythroblast, the earliest recognizable erythroid precursor, is large with a prominent nucleus and basophilic cytoplasm.
Step 3: Second stage – Basophilic erythroblast.
This cell is smaller than the proerythroblast and exhibits intensely basophilic cytoplasm due to abundant ribosomes.
Step 4: Third stage – Polychromatic erythroblast.
Cytoplasm at this stage displays mixed staining (blue and pink) as ribosomes decrease and hemoglobin production rises.
Step 5: Fourth stage – Orthochromatic erythroblast.
This cell is largely filled with hemoglobin; its nucleus becomes pyknotic and is eventually extruded.
Step 6: Fifth stage – Reticulocyte.
Post-enucleation, the cell is a reticulocyte, retaining some ribosomal RNA. Reticulocytes mature into RBCs in circulation.
Step 7: Conclusion.
The correct sequence of erythropoiesis is: Proerythroblast → Basophilic erythroblast → Polychromatic erythroblast → Orthochromatic erythroblast → Reticulocyte.
Final Answer:
\[
\boxed{\text{The correct sequence is (A) D, A, B, E, C.}}
\]