Which of the following can be a part of a fire-resistive assembly?

A smoke partition is designed specifically to limit the movement of smoke within a building during a fire, making it an integral part of fire-resistive assemblies. By preventing smoke from spreading to other areas, smoke partitions help to protect means of egress, maintain visibility, and enhance the safety of occupants and first responders. The materials and construction used in smoke partitions are generally selected to achieve the necessary fire-resistive ratings, thus they contribute to the overall fire safety strategy of a building.

In contrast, while partition walls can provide some degree of fire resistance depending on their construction, they are not typically classified as a dedicated fire-resistive assembly. Entrance doors may feature fire-rated designs, but not all entrance doors suffice for a full fire-resistive assembly. Similarly, while heating ducts can be designed to resist fire under certain circumstances, they are generally not categorized as fundamental components of fire-resistive assemblies. Thus, a smoke partition stands out as the clear choice in this context, focusing on controlling smoke movement, which is a critical aspect of fire safety measures.