Four Equal Charges Are Located at the Corners of a Square

Multiple Choice

Four equal charges are located at the corners of a square of side d. If the magnitude of each charge is doubled, then what happens to the resultant force on each charge?

A) It is doubled.
B) It is quadrupled.
C) It increases by a factor of 8.
D) It remains the same.
E) None of the other choices is correct.