Who practiced medicine in Philadelphia for 50 years?

Dr. Oscar J. Cooper is recognized for his long and dedicated career in medicine, having practiced in Philadelphia for 50 years. He was an exemplary figure within the Omega Psi Phi Fraternity and is known for his contributions to both the medical field and the community. His extensive experience not only showcases his commitment to medicine but also reflects the importance of skilled African American practitioners during a time when they faced significant barriers in their professional development.

The other individuals mentioned in the options made significant contributions in various capacities, such as education, religion, and science, but they did not have the same lengthy medical practice in Philadelphia as Dr. Oscar J. Cooper. Thus, his unique legacy as a practicing physician sets him apart in this context.