Two free positive charges 4q and q are a distance apart. What charge q is needed to achieve equilibrium for the entire system and where should it be placed from charge 4q?
A) q = 2q, placed at 2/3 distance from 4q
B) q = 3q, placed at 3/4 distance from 4q
C) q = 4q, placed at 4/5 distance from 4q
D) q = 5q, placed at 5/6 distance from 4q