Which vehicle is defined as having 2 tandem wheels, at least one of which is more than 14 inches in diameter?

The correct answer is that a vehicle defined as having 2 tandem wheels, at least one of which is more than 14 inches in diameter, is a bicycle. This definition aligns with specific regulations that categorize bicycles based on their wheel configurations and sizes. Bicycles typically have two wheels, and when they are described as having tandem wheels, it indicates that the two wheels are arranged in such a way that both are aligned next to each other, which is common for many bicycle designs.

In contrast, trucks, buses, and motorcycles have different configurations and characteristics that do not fit this specific definition. Trucks and buses generally have configurations that include more than two wheels and are built for carrying larger loads or more passengers. Motorcycles also do not typically fall under this definition as they are designed with a different wheel setup and are classified separately due to their engine and structural specifications. Therefore, a bicycle is the only option that accurately conforms to the presented definition.