Among the choices, which is considered a firestop product?

Firestop Mortar is specifically designed to seal openings and joints in fire-rated wall and floor assemblies. Its primary function is to prevent the passage of fire, smoke, and toxic gases between fire-resistance-rated assemblies, thereby helping to maintain the integrity of the structure during a fire. Firestop Mortar is tested and labeled to various fire resistance standards, ensuring that it effectively meets the requirements set forth in building codes for fire protection.

Other materials listed, like Wood Filler, Bubble Wrap, and Cement Board, do not possess the same fire-resistive properties or functionality associated with firestop systems. Wood Filler is used for repairing and finishing wood surfaces, Bubble Wrap is primarily a packaging material with no fire-resistive capabilities, and while Cement Board may have some fire-resistant properties, it is not designed specifically as a firestop material. Therefore, Firestop Mortar is the only option that meets the criteria necessary for a firestop product.