How many mirrors should a motorcycle have at a minimum?

A motorcycle should have at least two mirrors to provide the rider with a clear view of the traffic behind them. This is essential for safe riding, as it helps the rider to be aware of their surroundings and other vehicles, which is crucial for making informed decisions while riding. Having two mirrors allows for a wider field of vision compared to a single mirror, reducing blind spots and enhancing overall safety.

The other answer choices, while they suggest having fewer or more mirrors, do not align with the safety regulations and best practices for motorcycle operation. A single mirror may not provide sufficient visibility of what is behind or alongside the motorcycle, and having four mirrors would be excessive and unnecessary for basic operation. Thus, the minimum of two mirrors strikes the right balance between safety and practicality for motorcycle riders.