Which organization primarily focuses on the professional development of business education?

The organization that primarily focuses on the professional development of business education is the National Business Education Association (NBEA). NBEA is dedicated to enhancing the teaching of business education at all levels and provides support through resources, professional development opportunities, and networking for educators in the field. This focus helps ensure that educators are effectively equipped with the necessary tools and knowledge to teach various aspects of business.

In contrast, Future Business Leaders of America (FBLA) is centered around developing leadership skills among students interested in business careers but does not directly provide professional development for educators. Phi Beta Lambda (PBL) is the collegiate counterpart to FBLA, also aimed at students rather than professionals in education. The U.S. Department of Education (USDE) plays a role in overseeing federal education policy and funding but does not specialize in the professional development of business education specifically. Thus, NBEA's singular focus on business education development sets it apart as the correct answer.