The correct answer is: A. Stone steps.
Stone steps are a type of step that is made from stone. They are typically used in outdoor settings, such as gardens and walkways. Stone steps can be made from a variety of stones, including granite, marble, and limestone. They can be either natural or man-made.
Stone steps are a durable and long-lasting type of step. They are also relatively easy to maintain. However, they can be expensive to install.
Built-up steps are a type of step that is made from multiple materials, such as concrete, brick, and stone. They are typically used in indoor settings, such as staircases. Built-up steps can be either straight or curved.
Spandril steps are a type of step that is located in the space between two arches. They are typically used in bridges and other architectural structures. Spandril steps can be either straight or curved.
None of these is the correct answer.