You have covered a grounded metal surface with a layer of photoconductor. working in the dark, you sprinkle negative charge onto this surface. if you now expose only the left half of the photoconductor to light, you will find that
(a) the left half becomes neutral while the right half remains negatively charged.
(b) nothing happens because there is no changing magnetic field.
(c) negative charge flows from the right side of the photoconductor to the left and both sides become neutral.
(d) the right half becomes neutral while the left half remains negatively charged.