Organic Soil Orders and 40 cm rule

Yes, that is correct....... if only Of is present it should be thicker than 60 cm. But in APBI 200 course we would accept as a correct answer even if Of is thicker than just 40 cm.
And if two or three O horizons are present, they collectively need to be thicker than 40 cm
Things are actually much more complicated than this in the classification of Organic soil order, but for our Intro course, this will do.

Thank you!