Pick up the correct statement from the following: A. In stone arches, the stones are placed with their natural beds radial B. In cornices, the stones are placed with their natural beds as vertical C. In stone walls, the stones are placed with their natural beds as horizontal D. All the above

The correct answer is D. All of the above.

In stone arches, the stones are placed with their natural beds radial. This means that the long axis of the stone is aligned with the radius of the arch. This helps to distribute the weight of the arch evenly and prevents it from collapsing.

In cornices, the stones are placed with their natural beds as vertical. This helps to prevent the cornice from breaking under the weight of the roof.

In stone walls, the stones are placed with their natural beds as horizontal. This helps to prevent the wall from collapsing under its own weight.

In all of these cases, the way in which the stones are placed is important for the structural integrity of the building.