Answer
Please see the work below.
Work Step by Step
(a) We know that when we draw a large number of equipotential surfaces with constant potential difference between adjacent surfaces, the equipotentials at point 2 are more closely spaced than equipotentials at point 1.
(b) We know the best explanation is option (III) -- that is, the electric field is more intense at point 2 than at point 1, which means the equipotential surfaces are more closely spaced in that region.
