Which of the following is NOT a recognized excavation protective system?

The correct answer is "D." Wrapping is not a recognized excavation protective system under OSHA regulations. Instead, the recognized protective systems include sloping, sheeting, and benching.

Sloping involves cutting back the sides of an excavation to a safe angle, reducing the risk of collapse. Sheeting refers to the installation of sheets or panels to prevent soil from falling into the excavation, providing a barrier that supports the walls. Benching is a method that creates horizontal steps or benches in the sides of the excavation, which helps to reduce the angle of the slope necessary for stability.

These systems are essential for ensuring worker safety during excavation work, and familiarity with these methods is crucial for preventing accidents and injuries on construction sites.