A contractor or subcontractor under a public work contract subject to this subtitle: shall employ only competent workers and apprentices who qualify under subsection (b) of this section; may not employ any individual classified as a helper or trainee; and may refuse to employ a worker who is a resident of another state if the Commissioner finds that the other state enforces a law that prohibits a resident of this State from employment as a worker under a public work contract in that state, unless: the refusal is in conflict or otherwise inconsistent with a federal law applicable to the public work; the federal government is to pay wholly or partly for the public work; and the inconsistency with federal law jeopardizes the availability of federal funds for the public work. An apprentice under a public work contract shall be part of and used in accordance with an apprenticeship program that: is registered with the Council and approved by the Office of Apprenticeship of the United States Department of Labor; and if the program has graduated at least one apprenticeship cohort, has a completion rate of at least 25%, as determined by the Maryland Department of Labor.