Which of the following substance can be flattened on beating with a hammer?

The correct option is D Piece of aluminium
A piece of aluminium can be flattened into thin sheets on beating with a hammer. The ability of any material to be beaten into sheets is known as malleability and is a property of metals. Non-metals are generally not malleable hence lump of sulphur, piece of coal and lump of phosphorous can not be beaten into thin sheets.