On a four-wheel steering system, the __ turns the wheels when commanded by the steering control module. a. Steering knuckle b. Actuator c. Tie-rod end d. Rack-and-pinion

## Step 1<br />In a four-wheel steering system, the steering control module commands the actuator to turn the wheels. The actuator is a device that moves or controls a mechanism or system. In this case, the actuator is responsible for turning the wheels when commanded by the steering control module.<br /><br />## Step 2<br />The steering knuckle, tie-rod end, and rack-and-pinion are all components of the steering system, but they do not directly turn the wheels when commanded by the steering control module. <br /><br />## Step 3<br />The steering knuckle is a pivot point for the wheel, the tie-rod end is a part of the steering linkage, and the rack-and-pinion is a type of gear arrangement. None of these components directly turn the wheels when commanded by the steering control module.