Which of the Following Statements Is NOT True

Which of the following statements is NOT true?

A) In the ECF, Na+ is accompanied primarily by Cl^- and to a lesser extent by HCO₃^-.
B) In the ICF K+ is accompanied by PO₄^3-.
C) In most organisms Na⁺ is the primary ion in the ICF.
D) A fluid compartment found in all animals is produced by the digestive tract.
E) All plasma constituents except proteins are freely exchanged between plasma and interstitial fluid.