Why Is Volume Regulation at Odds with Ionic Regulation in Marine

Why is volume regulation at odds with ionic regulation in marine teleost fish?

A) Volume regulation is not at odds with ionic regulation in marine teleost fish, only in freshwater teleost fish.
B) Salts in the marine teleost absorb water from the ocean, which must be eliminated.
C) In order to maintain osmotic balance, salts must be taken in from the ocean water.
D) The only way to obtain water is to drink it, which loads more salt into the animal which must be eliminated.