Answer
The correct answer is:
(c) A, B, and C
Work Step by Step
We can find a general expression for the electric potential at a point:
$V = \frac{k~Q}{r_1}+\frac{k~Q}{r_2}-\frac{k~Q}{r_3}-\frac{k~Q}{r_4}$
At points A, B, and C:
$r_1 = r_3$ and $r_2 = r_4$
Then $V = 0$
At point D:
$r_1 \lt r_3$ and $r_2 \lt r_4$
Then $V \gt 0$
At point E:
$r_1 \gt r_3$ and $r_2 \gt r_4$
Then $V \lt 0$
The correct answer is:
(c) A, B, and C
