Umbric Epipedon: In USDA Soil Taxonomy, an umbric epipedon meets all the morphological requirements of a mollic epipedon (thick, dark color with value $\le 3$ and chroma $\le 3$, high organic matter, remains moist $\gt 9$ months per year) except that its base saturation is less than 50% ($NH_4OAc$ method).
Other Epipedons:
Mollic: High base saturation ($\ge 50\%$).
Ochric: Light-colored or thin epipedon lacking diagnostic criteria.
Melanic: Very dark volcanic epipedon rich in allophane and humus. (Correct answer: Option 3)
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