Two Charged Point Particle Are Located at Two Vertices of an Equilateral

Multiple Choice

Two charged point particle are located at two vertices of an equilateral triangle and the electric field is zero at the third vertex. We conclude:

A) the two particles have charges with opposite signs and the same magnitude
B) the two particles have charges with opposite signs and different magnitudes
C) the two particles have identical charges
D) the two particles have charges with the same sign but different magnitudes
E) at least one other charged prticle is present