thE rElAtionship BEtwEEn A BACtErium AnD its FlAgEllA is most nEArly AnAlogous to whiCh oF thE Following
A．A riDEr jumping on A horsE's BACk.
B．A BAll BEing hit By A BAt.
C．A BoAt powErED By A motor.
D．A Door ClosED By A gust oF win