Which of the following poses a particular danger to motorcyclists and can compel them to change their position?

Gravel poses are a particular danger to motorcyclists and can compel them to change their position.

Explanation:

The gravel under the tires of a motorcycle moving at a high speed can cause it to skid and slip. Hence, motorcyclists often prefer clean and clear roads for rides. If there is gravel spread on the roads, it is advised that the motorcyclists reduce their speed and cross the patch that has gravel on it at the minimum possible speed. This is because the tires of a motorcycle are not as broad as that of a car and it has to be balanced on just two wheels, which is not the case with car.