Charges Are Placed at the Corners of a Square Whose

Multiple Choice

Charges are placed at the corners of a square whose sides are 2.0 m in length. The charges are +4.0 nC at (0, 0) , +3.0 nC at (2.0, 0) , -3.0 nC at (0, 2.0) , and +4.0 nC at (2.0, 2.0) . The magnitude of the force exerted on a +1.0-nC test charge placed at the square's center is

A) 0 N.
B) 4.5 *10^-9 N.
C) 27*10^-9 N.
D) 32 * 10^-9 N.
E) 45 * 10^-9 N.