Where were the Sophists and philosophers usually taught_____________?

A. Galleries
B. Schools
C. Universities
D. Libraries

Sophist, (highly paid professional teachers) any of certain Greek philosophers, lecturers, writers, and teachers in the 5th and 4th centuries BCE, and most of whom traveled about the Greek-speaking world giving instruction in a wide range of subjects in return for fees. They were the sole source of higher education in the more advanced knowledge. After getting their proper education, they would sent to learn artifacts and practical methodology from galleries.
Galleries were the special training centers for them, where they trained as professional teachers