The first step in digestion starts with
tongue
esophagus
saliva

Saliva contains an enzyme called salivary amylase. 

Salivary amylase is an enzyme that breaks down complex carbohydrates molecules into simple or smaller carbohydrate molecules  called maltose. The enzyme acts on carbohydrates in the mouth, initiating the process of digestion.

Salivary amylase  is made by the salivary glands in the mouth. Maltose is later converted to glucose in the small intestine by another type of amylase called pancreatic amylase.  

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.

i believe your answer would be c.. : )