What do eaves refer to in building terminology?

Eaves refer to the edge of the roof that overhangs the wall, making choice B the correct answer. This architectural feature serves both functional and aesthetic purposes. Functionally, eaves help to direct rainwater away from the walls and foundation of a building, thereby preventing water damage and erosion. They can also provide shade by blocking direct sunlight from hitting the windows during certain times of the day, contributing to energy efficiency and comfort within the building.

In contrast, the other options pertain to different components of a building. The walls of a building refer to the vertical structures that define and enclose the space inside. The base of the foundation refers to the lower part of the structure that supports the entire building, typically designed to ensure stability. Interior ceiling material involves the finishes found on the inside ceilings of a building, which can impact aesthetics and acoustics but is unrelated to the roof's edge. Understanding the role and function of eaves is important in building construction and maintenance, as they play a critical role in protecting the integrity of the structure.