What unique feature distinguishes a motorized seat belt system?

The unique feature that distinguishes a motorized seat belt system is that the shoulder belt attaches to a motor running inside the door. This configuration allows for the shoulder belt to be retracted or extended automatically based on the user's needs or preferences. It minimizes the need for manual adjustment, providing an enhanced level of convenience and safety for the occupant.

In contrast, other options describe various aspects of seat belt design that may exist in different types of systems, but they do not specifically highlight the motorized feature unique to this setup. For instance, while a lap belt may be motorized as well, that characteristic alone does not set apart a motorized seat belt system. Similarly, while components being electronically controlled is common in many modern safety systems, it is not exclusive to motorized seat belts. Lastly, the automatic adjustment of the shoulder belt to the driver's height, while it can enhance fit and safety, does not specifically describe a complete motorized system's functionality, as it typically relates to the design and adaptability of the seat rather than the belt mechanism itself.