What is the diameter of the 300 ft hose line equipped with a breakaway smooth bore nozzle on the officer side outside rear discharge?

The diameter of the 300 ft hose line equipped with a breakaway smooth bore nozzle typically aligns with standard specifications for fire hoses used in firefighting operations. A hose line designed for suppressing fires is generally structured to provide an effective flow of water while maintaining manageable maneuverability.

In this context, the correct diameter of the hose line would be 1¾ inches. This size is widely recognized as a standard for fire attack hoses, balancing flow capacity with ease of handling. It is optimal for operations requiring agility and effectiveness in maneuvering around obstacles and during firefighting scenarios.

The other diameter options, while applicable in different contexts or systems, do not match the standard practices for a hose line that is both functional and practical for the intended use described in the question. For instance, a 2-inch or larger hose may be used for supply lines or larger volume needs, while a 5-inch hose is typically reserved for large diameter supply lines intended for higher flow rates. Thus, 1¾ inches stands out as the appropriate choice for a 300 ft hose line with a breakaway smooth bore nozzle.