What is the correct sequence when defining units of mea…

What is the correct sequence when defining units of measure (UOM)?

A.
UOM Class, UOM, UOM Conversions

B.
UOM Class, UOM Conversions, UOM

C.
UOM Conversions, UOM Class, UOM

D.
UOM Conversions, UOM, UOM Class

E.
UOM, UOM Class, UOM Conversions