During a lightning flash, -11 C of charge moves through a potential difference of 8.1×10^7 V. What is the net electric field at x = -4.04 cm?
a) -2.5 × 10⁵ N/C
b) 3.1 × 10⁶ N/C
c) 1.9 × 10⁵ N/C
d) -4.8 × 10⁶ N/C