Sally puts a plant in front of the window and a plant 10 meters back from the window. Keeping all other conditions the same. What gas output will she be monitoring and what will she most likely see?

a
She is monitoring oxygen and she should see the plant farthest from the window gives off the most oxygen.

b
She is monitoring carbon dioxide and the plant farthest from the window gives off the most carbon dioxide.

c
She is measuring oxygen and the plant farthest from the window gives off the most oxygen.

d
She is measuring oxygen and the plant closest to the window gives off the most oxygen.