Final answer:
To engage engine braking in the Kovatch-Series R-11, low gear should be used as it allows the engine to provide resistance and slow the vehicle down.
Step-by-step explanation:
To use engine braking in the Kovatch-Series R-11, the gear selector position that can be used is low gear. When a driver selects low gear while descending a steep grade, for instance, the engine's revolutions per minute (RPM) will increase, providing resistance through the drivetrain which slows the vehicle down.
This is preferable to neutral gear, which disconnects the engine from the wheels, and reverse gear and park gear, which should never be used while the vehicle is in motion as they can cause significant damage to the transmission.