Which department of the AFL-CIO supports building and construction trade unions?

The correct choice is the North American Building Trade Unions (NABTU), as this organization specifically represents the interests of the building and construction trade unions within the AFL-CIO. NABTU focuses on various aspects critical to the construction industry, including labor standards, working conditions, and collective bargaining rights. By serving as a collective voice for workers in the construction trades, NABTU plays a vital role in advocating for their rights and interests at both national and local levels. This makes it distinct from other organizations, which may not specifically focus on the building and construction sectors.

The other options, while they may relate to labor unions in a broader sense, do not have the specific focus on building and construction trades that NABTU does.