Sidewise force of the propeller tends to throw a vessel’s stern to the right or left，depending on rotation. This force is caused by（）.

A. back current from the rudder
B. greater pressure on the right or left side of the propeller，depending on rotation
C. lower pressure on the right or left side of the propeller，depending on rotation
D. torque from the velocity and angle at which the surrounding water impinges upon the propeller blade