Which of the following is not a protective shoring system option?

The reasoning behind identifying an un-sloped trench with no shoring as not being a protective shoring system option is rooted in safety practices for excavation and trench work. A shoring system is designed to provide support and prevent the collapse of soil around workers in an excavation.

When working in a well-sloped trench or using trench boxes and hydraulic shoring, safeguards are in place to mitigate the risks of cave-ins. A well-sloped trench utilizes a natural angle of repose, which is carefully calculated to avoid soil loss and collapses. Similarly, trench boxes and hydraulic shoring are engineered systems that offer strong support to the walls of a trench.

In contrast, working in an un-sloped trench without any form of shoring completely disregards safety regulations and best practices, exposing workers to significant risks from soil movement and potential injury from collapses. Therefore, this option is clearly not recognized as a legitimate protective shoring system.