The correct answer is: A. Retaining wall
A retaining wall is a structure that is used to hold back soil or other materials. It is typically made of concrete, masonry, or stone, and it can be either vertical or sloped. Retaining walls are often used in landscaping to create terraces or to support slopes.
A breast wall is a short retaining wall
that is typically used to support a low embankment or to protect a foundation from erosion. It is usually made of stone or concrete, and it is often topped with a coping stone to prevent water from running over the top.A buttress is a structure that is used to support a wall or other structure. It is typically made of masonry or concrete, and it is often built at an angle to the wall that it is supporting. Buttresses are often used in Gothic architecture to support the weight of the roof.
A parapet wall is a low wall that is built along the edge of a roof or other elevated structure. It is typically made of stone or concrete, and it is designed to prevent people from falling off the edge. Parapet walls are often
used on bridges and other structures where there is a risk of falling.