Two point q and -q are placed at the vertices b and c of an equilateral triangle abc of side a. What is the arrangement of charges in the triangle?
1) Positive charge at vertex a and negative charges at vertices b and c
2) Negative charge at vertex a and positive charges at vertices b and c
3) Positive charge at vertex a and positive charges at vertices b and c
4) Negative charge at vertex a and negative charges at vertices b and c
