Which of the following is an example of a simple training evolution?

The choice of using a portable fire extinguisher as an example of a simple training evolution is correct because it involves a straightforward, focused practice that can be easily managed and controlled in a training environment. This task requires basic skills such as proper handling and operation of the extinguisher, understanding the different classes of fire, and executing the PASS technique (Pull, Aim, Squeeze, Sweep).

Simple training evolutions are typically characterized by their manageable scope, limited complexity, and the ability to be conducted in a variety of settings, often within a confined area. In contrast, live-fire exercises, hazardous material training, and above and below grade rescues involve more advanced skills, coordination, and safety considerations. These activities often require more extensive resources, preparation, and oversight, making them less suited to the definition of a simple training evolution.