The problem shown was most likely caused by which issue?

• A. Inadequate differentiation
• B. Over differentiation
• C. Insufficient dehydration
• D. Excessive clearing

Answer: (A)

The key idea is how the differentiation step in hematoxylin staining controls nuclear staining intensity. If differentiation is inadequate, not enough hematoxylin is removed, so the nuclei stay excessively dark and the contrast between nucleus and cytoplasm is reduced. This matches a problem where nuclear detail is overly intense or muddied by over-staining. If differentiation were too strong, the nuclei would be pale and lose detail, which would look different. Dehydration or clearing issues affect tissue morphology or clarity of mounting more than the staining intensity of nuclei, so they’re less likely to explain the observed problem. Therefore, the issue is inadequate differentiation.