During an autorotation in forward flight, the rotor disk takes in ___ air and the driven, driving, and stall regions of each blade move ___ along its length (span), but only on the ___ side of the disk:
A. upward flowing, outboard, retreating.
B. downward flowing, inward, advancing.
C. upward flowing, inward, retreating.
D. ambient, outward, advancing.