What is hydroplaning?

Hydroplaning occurs when a vehicle's tires lose contact with the road due to the presence of water, causing the vehicle to ride on the surface of that water. This phenomenon typically happens at higher speeds when there is a significant volume of water on the road. As the vehicle's speed increases, the tires cannot displace the water quickly enough, resulting in a loss of traction, control, and increased risk of accidents.

In this case, the answer encompasses both aspects: the loss of contact with the road due to speed (which illustrates the conditions under which hydroplaning occurs) and the floating effect on the surface of water, which describes the state of the vehicle during hydroplaning. Hence, selecting an answer that includes both A and C accurately represents the complete nature of hydroplaning and its effects on vehicle handling.