The above shows isoelectric lines generated by two charged particles \(q_1\) and \(q_2\) fixed on the \(x\)-axis of an \(xy\)-plane, where \(q_1\) is a positively charged particle. The points \(A,\) \(B\) and \(C\) are also on the \(x\)-axis with the distances from the origin being \(d,\) \(3d\) and \(5d,\) respectively. The isoelectric line passing through the point \(B\) is parallel to the \(y\)-axis, and the point \(D\) is on this isoelectric line. Which of the following statements is NOT correct?
a) \(q_2\) is a negatively charged particle.
b) The voltage at the point \(A\) is higher than the voltage at the point \(B\).
c) If we put a positive charge on the point \(B\), then it does not move.
d) The direction of the electric field at the point \(A\) is the same as that at the point \(C\).