What was the lower class called in ancient Rome?

The correct answer is B. Plebeians.

In ancient Rome, the society was divided into two main classes: the Patricians and the Plebeians. The Patricians were the higher-status citizens, often wealthy landowners, while the Plebeians were the lower class, consisting of common people, including farmers, laborers, and craftsmen. The Plebeians had fewer rights and privileges compared to the Patricians but played a crucial role in the development of Roman democracy.