(a) A contractor or subcontractor under a public work contract subject to this subtitle: (1) shall employ only competent workers and apprentices who qualify under subsection (b) of this section; (2) may not employ any individual classified as a helper or trainee; and (3) 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: (i) the refusal is in conflict or otherwise inconsistent with a federal law applicable to the public work; (ii) the federal government is to pay wholly or partly for the public work; and (iii) the inconsistency with federal law jeopardizes the availability of federal funds for the public work. (b) An apprentice under a public work contract shall be part of and used in accordance with an apprenticeship program registered with the Council and approved by the Office of Apprenticeship of the United States Department of Labor.