Identifying leukocytes by morphological features

Steps:

• Examine cell size, nucleus shape, and cytoplasm characteristics in the blood smear.
• Label 1 shows largest cell with indented/kidney-shaped nucleus and abundant pale cytoplasm: monocyte.
• Label 2 displays segmented multi-lobed nucleus and fine granules: neutrophil.
• Label 3 has small size, large round nucleus, and scant cytoplasm: lymphocyte.

Why D is correct:

• D matches standard WBC morphology: monocytes are largest with horseshoe nuclei, neutrophils have 3-5 lobes, lymphocytes are smallest with round nuclei (per hematology definitions).

Why the others are wrong:

• A: Swaps monocyte and lymphocyte; monocytes exceed lymphocytes in size.
• B: Mislabels monocyte as neutrophil; monocytes lack multilobed nuclei.
• C: Confuses monocyte and lymphocyte; lymphocytes have round, not indented, nuclei.

Final answer: D