Answer: Option D.
Extracellular fluid should be isotonic to intracellular fluid.
Step-by-step explanation:
Homeostasis refers the way and ability living organisms regulate their internal environment to be abele to survive.
Extracellular fluids refers to fluid outside the body cells. It is important organisms keep their extracellular fluid constant especially with regard to osmotic pressure, pH, temperature.
Extracellular fluid should be isotonic or have the same osmotic pressure with the intracellular fluids to maintain osmosis.
Intracellular fluid is fluid within the body cells.