Use the Following Information When Answering the Corresponding Question(s)

Use the following information when answering the corresponding question(s) .
The shade avoidance response is a plant's way of changing its growth pattern when it is being shaded by another plant.Upon exposure to shade,many plants will grow taller,flatten their leaf angle,and extend their leaves further from their stems in order to reach full sunlight.Research performed by Pierik et al.(Interactions between ethylene and gibberellins in phytochrome-mediated shade avoidance responses in tobacco.2004.Plant Physiology 136:2928-36;online at http://www.plantphysiol.org/cgi/content/full/136/2/2928) examined the role of ethylene and gibberellins on the shade avoidance response in tobacco plants.The shade avoidance response is known to involve phytochromes.
-Refer to the paragraph on the research done by Pierik et al.When the researchers inhibited the synthesis of gibberellins in the tobacco plants,neither ethylene nor far-red light could trigger a shade avoidance response.Taken together with the data presented above,these data suggest that gibberellins _____.

A) act in concert (work together) with ethylene to generate the shade avoidance response
B) antagonize (act oppositely) the effects of ethylene on the shade avoidance response
C) are not involved in the shade avoidance response