Identify the correct sequence of labelled A, B, C and D of the following diagram of a part of the peel of a dicot leaf seen with a compound microscope:

A destarched leaf on a potted plant was covered with black (A), white (B), and transparent (C) strips of paper, as shown in the figure. After six hours of exposure to sunlight, the leaf was removed from the plant and tested for starch. Which one of the following will be the correct observation?