Select the correct statement:
A.A.The primary flight controls are powered by hydraulics systems A & B, with backup from the standby hydraulic system for the rudder and manual reversion for the rest
B.B.Flight spoilers are used both for roll control, descent and decelaration
C.C.The trailing edge flaps can be both extended and retracted using the Alternate Flap drive system.
D.D.All statements are correct
正确答案是D