A lap-only belt with no retractor is locked using which part?

In a lap-only belt system that does not have a retractor, the locking mechanism is primarily facilitated by the latch plate. The latch plate is the component that holds the seatbelt tongue securely in place, locking it into the buckle. When the seatbelt is installed properly, the latch plate prevents any movement of the seatbelt, effectively securing the occupant in place.

The latch plate plays a crucial role in maintaining the integrity of the seating position during a crash, as it ensures that the seatbelt does not allow for excessive slack or movement. This is particularly important because a lap-only belt must hold the occupant securely to prevent injury.

While other components like the locking clip or the buckle have specific uses and functions in various contexts, they do not serve as the primary locking mechanism in a lap-only belt without a retractor. The shoulder strap is not relevant in a lap-only system, as this type of belt does not include a shoulder strap. Thus, the latch plate is the correct answer because it is the key component responsible for locking the lap belt in place.