Regarding scuba diving, which statement is incorrect? ( )

A、Scuba diving is a form of underwater diving in which a diver uses a self-contained underwater breathing apparatus (SCUBA) to breathe.
B、Essential scuba gear includes tanks, scuba diving masks, buoyancy compensation devices (BCD), regulators, fins, wetsuits and safety sausages.
C、Scuba diving is a risk-free sport.
D、Before you go scuba diving, you will need some training from a qualified scuba diving instructor.