So, my language intuition is at a bit of an impasse. I'm describing the contents of a study module and I've arrived at the following sentence: "The qualification consists of...and one optional unit selected out of the units Inspection, Archaeology, or Science."
I'm having trouble deciding whether the definite article is necessary here. "out of units X1, X2, and X3" sounds equally correct. For what it's worth none of these units have been previously mentioned in the text; still, I'm left thinking if the fact that I'm defining the units of which I speak required the definite article or if I can use null article here?