Tony sets up an experiment inside his classroom. He spaces 5 plants at equal distances along a straight line, with the first plant directly in front of a window and the last plant 10 meters (m) away from the window. He gives them equal access to air and water and then monitors the amount of gas each plants releases. A. He is monitoring oxygen. The amount of gas released should be highest for the plant in the middle and lowest for the plants at the ends

B. He is monitoring carbon dioxide. The amount of gas released should be highest for the plant in the middle and lowest for the plants at the ends.

C. He is monitoring oxygen. The amount of gas released should be highest for the plant closest to the window and the lowest for the plant farthest away from the window

D. He is monitoring carbon dioxide. The amount of gas released should be highest for the plant closest to the window and lowest for the plant farthest away from the window.