The answer is (b): the reading will indicate a smaller voltage or a smaller charge, as seen in an mpeg video by clicking your mouse on the photograph below.
When a positively charged rod is brought close to the terminal, it pulls electrons out of the electroscope toward the terminal. Because the electroscope was charged negative by induction, pulling away some of the charge results in a smaller charge, or a smaller voltage, on the electroscope, as observed.
