What document can evidence technical qualifications for a type PL license?

The correct choice is proof of registration as a professional engineer, as this document serves as a formal verification of an individual’s technical qualifications and expertise in engineering. Holding a license as a professional engineer indicates that the person has met specific education and experience requirements and has passed a rigorous examination, ensuring that they possess the necessary knowledge and skills to practice safely and competently in their field.

While a copy of previous licenses may show a history of licensure, it does not specifically validate current technical qualifications for the type PL license. A signed letter from a co-worker may provide anecdotal support for someone's abilities, but it lacks the formal recognition that comes with professional engineer registration. A training completion certificate could demonstrate participation in a related course, but it does not equate to the comprehensive qualifications required for licensing in a professional capacity. Therefore, proof of registration as a professional engineer is the strongest evidence of technical qualifications.