what do stairs wider than 30\ typically require?\n○ purlin\n○ mid - rib riser\n○ housed stringer\n○ center…

Brief Explanations:

In construction, stairs wider than 30 inches typically require a housed stringer. A housed stringer is designed to support the treads and risers of the stairs and is commonly used for wider - width stairs to ensure stability and safety. Purlin is mainly used in roof construction, mid - rib riser is not a standard requirement for wider stairs, and center cutout stringer is not the typical need for such stairs.

Answer:

C. housed stringer