All fire door assemblies must bear the label of an approved agency and include the maximum ____.Group of answer choiceshourly rating designationopening forcetensile strengthstrength rating

To determine the answer to the question, we need to understand the requirements for fire door assemblies.

Step 1: Fire door assemblies must bear the label of an approved agency. This means that the fire door must have a label or certification from a recognized and authorized agency that verifies its compliance with fire safety standards.

Step 2: The fire door assembly must include the maximum hourly rating designation. The hourly rating designation indicates the amount of time the fire door can withstand fire and prevent its spread. It is usually expressed in terms of hours, such as 1 hour, 2 hours, etc.

Step 3: Therefore, the correct answer to the question is the "hourly rating designation." This is the maximum amount of time that the fire door assembly can resist fire and prevent its spread.