Answer:
Option (2).
Explanation:
The cell potential or membrane potential may be defined as the difference in the electric potential between inside and outside of the cell. The membrane potential of the cell changes during the propagation of action potential.
The resting membrane potential is -70mV. The influx of sodium ions causes the depolarization of the cell membrane. The cell potential changes from -70mV to + 30mV. The membrane potential becomes more positive during the depolarization phase.
Thus, the correct answer is option (2).