What is the normal concetration of extracellular potassium?

A)110 mM
B)1000 mM
C)12 mM
D)140 mM
E)4.5 mM

D) 140 mM

The normal concentration of extracellular potassium is approximately 4.5 mM. Therefore, the correct answer is E) 4.5 mM.