The correct answer is B - rotation of the earth.
The coriolis effect is the apparent curvature global winds, ocean currents, and everything that moves freely across the surface of the earth.
The curvature is due to earth rotating on its axis. The effect was discovered by the 19th century French engineer Gaspard. C. Coriolis.
He used mathematical formulas to explain that the path of any object set in motion above a rotating surface will curve in relation to objects on that surface.