Fish in a Marine Environment Must Maintain a Relatively Constant

Fish in a marine environment must maintain a relatively constant ion concentration in their tissues and blood. How do the chloride cells in the gills aid fish in the removal of excess ions?

A) The chloride cells create a countercurrent system where ions are lost from the body and water is absorbed to dilute other ions (NaCl) .
B) The chloride cells create a countercurrent system where water is lost from the body and chloride ions are absorbed.
C) The chloride cells actively move ions into the body and water follows by osmosis.
D) The chloride cells actively remove ions from the body and water follows by osmosis.