Soils of which soil order have no diagnostic horizon

Answer: Option B

A diagnostic horizon in a soil layer is a combination of characteristics typical of that kind of soil. Certain features are illuvial iron- manganese coatings, depth of water table, texture, presence of organic matter, etc.
Entisols are the soil order that has no diagnostic horizon, entisols are the most abundant soil order, occupying about 16% of the global ice-free land area.