The position of a brick when laid on its side 9 cm × 9 cm with its frog in the vertical plane, is called A. Brick on edge B. Brick on end C. Brick on bed D. Brick held vertically

The correct answer is: A. Brick on edge.

A brick on edge is a brick that is laid on its side with its frog in the vertical plane. The frog is the indentation on the underside of the brick that helps to distribute the weight of the brick evenly. When a brick is laid on edge, it is more stable than when it is laid flat. This is because the frog provides additional support for the brick. Bricks are often laid on edge when they are used to build walls or other structures.

Option B, Brick on end, is incorrect because a brick on end is a brick that is laid on its end with its frog in the horizontal plane. This is not a stable position for a brick, and it is not typically used in construction.

Option C, Brick on bed, is incorrect because a brick on bed is a brick that is laid flat with its frog facing down. This is the most common position for a brick, and it is used in a variety of construction applications.

Option D, Brick held vertically, is incorrect because a brick held vertically is not a stable position for a brick. This position is not typically used in construction.