The correct statement regarding the role of the Coriolis effect on ocean currents is: The Coriolis effect turns currents clockwise in the Southern Hemisphere.
Additionally, it is also true that the Coriolis effect causes winds to turn to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. However, since you're looking for the role specifically related to ocean currents, the primary assertion about ocean currents is the one concerning their clockwise movement in the Southern Hemisphere.