Describe the two types of ocean currents

Deep water areDeep water currents are water movement patterns that take place more than 400 meters below sea level. They are influenced by both ocean density and temperature changes. Cooler water has a higher salt density than warm water, so as currents flow through cool areas, the warmer water in that region rises and the cool water flowing into the area sinks. This pattern continues as water currents travel through broad temperature zones and climate regions. The rising and sinking water actions cause the movement we call currents.
measuring currents are Both types of ocean currents are measured using units called Sverdrup (Sv). Sverdrup measures current flow rates, where 1 Sv is equal to 10 to the 6th power cubic meters per second, or about 265 million gallons per second. While ocean currents themselves can have flow rates of hundreds or thousands of Sv per second, the total Sv flow for all the fresh water sources in the world is only equal to about 1 Sv. This helps demonstrate the massive power and speed that ocean currents are capable of.

Ithink it would be choices a and b. hope this !