If I were to measure the distribution of ions in 2 unknown biological fluids and determined that fluid 1 has a high concentration of K+ and fluid 2 has a high concentration of Cl-, then those fluids would likely be:
Fluid 1: ICF and Fluid 2: ECF
Fluid 1: ECF and Fluid 2: ICF
Fluid 1: ECF and Fluid 2: ECF
Fluid 1: ICF and Fluid 2: ICF