What is the strength of the electric field of a point charge of magnitude +4.8 × 10^-19 C at a distance of 4.0 × 10^-3 m? A. 3.6 × 10^-4 N/C B. -2.7 × 10^-4 N/C C. -3.6 × 10^-4 N/C D. 2.7 × 10^-4 N/C