Two Point Charges, a and B, Lie Along a Line

Two point charges, A and B, lie along a line separated by a distance L. The point x is the midpoint of their separation.
-Which combination of charges would yield the greatest repulsive force between the charges?

A) -2q and -4q
B) +1q and -3q
C) -1q and -4q
D) -2q and +4q
E) +1q and +7q