Final answer:
The part of a pier that supports the thrust of a flying buttress is called an abutment. It is a crucial component in Gothic architecture, ensuring stability of the structure by redirecting lateral forces to the ground.
Step-by-step explanation:
The part of a pier that rises to take the thrust of a flying buttress is known as an abutment. In Gothic architecture, the purpose of flying buttresses was to redirect the forces from the pointed arches to the ground, thereby supporting the weight of the high walls by carrying the pressure of the lateral thrust and stabilizing the walls. They projected from the walls to a foundation and became an integral part of the structure. The correct answer to the provided question is C. Abutment.
During the Gothic era, flying buttresses became standard in building tall cathedrals due to their efficiency in halting the fracturing of thin walls. These architectural elements allowed buildings to have taller and more slender walls, with large windows that filled the interior with light, evoking a heavenly atmosphere. The additional support provided by the buttresses and the pinnacles on top also enhanced the structural stability of the buildings.