Explanation: The Edison-type storage cell, also known as a nickel-iron battery, utilizes specific materials for its electrodes. The positive plate is made of nickel(III) oxide-hydroxide, often referred to as nickel oxide or "green oxide of nickel" when in its discharged or initial form (nickel(II) hydroxide), which is typically a greenish material. This material is packed into steel tubes for structural integrity. Option A, "Finely powdered pure iron," describes the material used for the *negative* plate of an Edison cell, not the positive. Option C, "Lithium oxide," is associated with lithium-ion batteries, a completely different chemistry, and not an Edison cell. Therefore, "Green oxide of nickel" correctly identifies the active material on the positive plate.