Final answer:
The deep currents of the Atlantic Ocean are characterized as cold and saline, a result of the thermohaline circulation process and the consumption of oxygen through the decomposition of organic material at lower depths.
Step-by-step explanation:
The water found in deep currents of the Atlantic Ocean is best described by option (b), which states that it is cold and salty with high salinity. Due to the nature of deep ocean currents, particularly those in the Atlantic, these waters tend to be cold as they originate from polar regions where the water temperature is low. Furthermore, these waters have higher salinity due to the process of thermohaline circulation, where melting sea ice and evaporation increase the salinity of the water making it denser and causing it to sink. Also, the deeper layers are generally oxygen-poor compared to surface layers because the water at deep levels is far from the surface where most oxygen exchange with the atmosphere takes place. Additionally, the decomposition of organic material consumes oxygen in these deeper layers. Hence, these characteristics define the cold, dense, and saline waters of the Atlantic Ocean's deep currents.