Stories in height include:

The correct choice reflects the definition of stories in height as recognized in life safety codes. Specifically, a story is defined as a space between the floor and ceiling of a building. When considering the various levels within a building structure, a story typically includes all occupiable areas above the level of exit discharge, which is where occupants exit safely to the outside.

The level of exit discharge represents the point of egress that leads directly to a public way, and it is essential for ensuring safe evacuation routes in emergencies. Understanding this concept is crucial for life safety planning as it influences the design and construction of egress systems and overall building safety.

On the other hand, mezzanines, interstitial spaces used for building systems, and stories below the level of discharge do not qualify as stories in height in the traditional sense. Mezzanines can be considered intermediate levels but are not always classified as full stories. Interstitial spaces primarily are used for mechanical systems and do not function as occupiable spaces. Stories below the level of discharge pose challenges for safe egress and do not conform to the traditional concept of a story in height when it comes to life safety regulations.