Answer:
(a). Sodium is needed to generate an action potential.
Step-by-step explanation:
Action potentials are generated when different ions move across the membrane of neurons. Sodium ions are responsible for depolarization during action potential by moving inside the cell through sodium channels.
When sodium ions are low in blood (hyponartremia), it shows dangerous effects on action potentials due to inhibition of normal cycle as sodium ions are not sufficient to depolarize the membrane.
Thus, the correct answer is option (a).