Final answer:
Architects are not considered to be in a specified service trade or business according to the U.S. Tax Cuts and Jobs Act, hence the correct answer is b. Architect.
Step-by-step explanation:
The question asks which self-employed individuals are not in a specified service trade or business, according to the U.S. Tax Cuts and Jobs Act (TCJA) introduced in 2017. Among the options provided, the correct answer is b. Architect. The TCJA defines a specified service trade or business as one which involves the performance of services based on reputation or skill in the fields of health, law, accounting, actuarial science, performing arts, consulting, athletics, financial services, and brokerage services. Architects and engineers were specifically exempted from this definition, meaning their businesses are not considered specified service trades or businesses.