Answer: A. The rotation of the earth on it's axis.
Explanation:
The rotation of the Earth on its axis deflects the atmosphere toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere, resulting in curved paths. The deflection of the atmosphere sets up the complex global wind patterns which drive surface ocean currents. This deflection is called the Coriolis effect. It is named after the French mathematician Gaspard Gustave de Coriolis (1792-1843), who studied the transfer of energy in rotating systems like waterwheels. (Ross, 1995).
