The electric field is E = 7.46 miliVolts/meter
If we multiply the electric field times the length of the membrane, we can find the voltage across it.
V = E*d
Where d = 9.67 E -9 m
V = 7.46 mV/m * 9.67 E -9 m = 7.213 E -11 V
The answer is 7.213 E -11 Volts