Ben wants to know if leaves are capable of making food during night-time. Which of the following experimental design should Ben do to get an accurate answer to his question?

A. Put one potted plant in a very dark place overnight and test for the presence of starch.

B. Cover the plant with paper bag overnight and test for the presence of starch.

C. Cover one leaf of a potted plant with carbon paper for two hours and test for the presence of starch.

D. Put one potted plant under the sun and the other in a shaded area for two hours and test for the presence of starch.​