Which Feature Does Not Characterize Osmoconformers

Which feature does not characterize osmoconformers?

A) They equilibrate osmolarity of extracellular fluid with that of the surrounding environment.
B) They include many marine invertebrates.
C) They save energy by not having to move ions across membranes.
D) They can maintain extracellular fluid at the osmolarity of fresh water.
E) Invertebrate osmoconformers regulate ions other than Na⁺ and Cl^-.