Which of the following is true regarding the use of a motor vehicle?

The statement about a motor vehicle being required to be self-propelled and not operated exclusively on tracks accurately captures the definition and nature of motor vehicles under Missouri law and general vehicles regulations. A motor vehicle typically refers to any machine capable of transporting people or goods, where the primary characteristic is that it has its own motive power, meaning it does not rely solely on external force or tracks, as in the case of trains.

This definition excludes vehicles that are specifically designed to operate exclusively on tracks, such as trains or trolleys, highlighting the importance of self-propulsion for categorizing vehicles as motor vehicles. This delineation is crucial in understanding the regulatory framework, which distinguishes motor vehicles from other types of transport based on their design and mode of operation.

The other provided options do not align with the established definitions or common regulatory practices. For instance, statements regarding limitations on vehicle use or seat capacity introduce misleading qualifications that do not reflect standard definitions used in legal frameworks concerning motor vehicle regulations. Thus, the essence of the correct option underlines significant legal considerations in categorizing vehicles within traffic laws and safety regulations.