Several Scientists,including Charles and Francis Darwin,Frits Went and Others,demonstrated That

Several scientists,including Charles and Francis Darwin,Frits Went and others,demonstrated that auxins caused stems to bend toward light in a series of elaborate experiments.Went was the researcher who finally determined that bending of the stem toward light was a result of which mechanism?

A) Light caused a reduction in auxin concentration and a reduction in stem elongation on the lighted side of the plant stem,and thus a bending in the direction of the light.
B) The transport of auxin to the shaded side of the plant stem stimulated stem elongation and a bending in the direction of the light.
C) Auxin concentration was equal on both sides (lighted and shaded) of the stem; however,the apical meristem responded to the presence of light.
D) A combination of positive phototropism and a negative gravitropism.
E) The stems actually were responding to the agar blocks that had been used in the experiments.