Final answer:
The sodium equilibrium potential with the given sodium concentrations would be approximately +71mV.
Step-by-step explanation:
The sodium equilibrium potential is determined by the concentration gradient and electrical gradient across the cell membrane. In this case, with an extracellular sodium concentration of 145 mEq/L and an intracellular concentration of 10 mEq/L the sodium equilibrium potential would be approximately +71mV (Option D).
The concentration gradient for sodium causes it to move into the cell, while the electrical gradient attracts the positively charged sodium ions towards the inside of the cell. The resulting voltage is measured as the resting membrane potential, and in this case, it would be around +71mV.