Can a driver change lanes while in a roundabout?

In a roundabout, the design and flow are specifically structured to enhance safety and efficiency. Drivers are required to yield to traffic already circulating in the roundabout, and this smooth flow is integral to preventing accidents. Changing lanes while in a roundabout can disrupt this flow and lead to confusion for other drivers, increasing the risk of collisions.

Therefore, the correct answer states that it is not allowed to change lanes while in a roundabout. This regulation helps ensure that drivers maintain their lane and makes it easier for vehicles to navigate the roundabout without unexpected lane changes that could cause dangerous situations.

The other options, although they might seem plausible in specific scenarios, do not align with the fundamental traffic rules for roundabouts, where consistency and predictability are essential for safe driving.