When Considering the Shadowed Side of a Grass Shoot,which of the Following

When considering the shadowed side of a grass shoot,which of the following best describes why it bends toward the light?

A) Reduction in auxin levels allows gibberellins to promote cell elongation.
B) Reduction in gibberellin levels allows auxin to promote cell elongation.
C) Increase in auxin levels promotes cell elongation.
D) Increase in auxin levels promotes cell proliferation.