What types of vehicles are included under the category of private passenger autos?

Private passenger autos are typically defined as vehicles primarily designed for the transportation of passengers. This category usually includes ordinary cars, SUVs, and light trucks that are used for personal use rather than commercial purposes. The correct choice identifies ordinary cars and utility trailers, which fit the description of vehicles mainly used by private individuals for personal transportation.

Utility trailers can sometimes be classified within this broader category if they are used in conjunction with personal vehicles for activities like transporting recreational gear or for light hauling, emphasizing their connection to the personal use of vehicles.

In contrast, the other options include vehicles or categories that serve primarily commercial or different transportation purposes. Commercial trucks and vans are designed for business use, company cars typically belong to a business, and motorcycles and buses serve different niches outside of the typical definition of private passenger vehicles. Therefore, the correct choice accurately represents the types of vehicles that compose the private passenger auto category, focusing on personal and non-commercial use.