Plants Growing in a Partially Dark Environment Will Grow Toward

Plants growing in a partially dark environment will grow toward light in a response called phototropism. Which of the following statements is true regarding phototropism?

A) It is caused by an electrical signal.
B) One chemical involved is ethylene.
C) Auxin causes a growth increase on one side of the stem.
D) Auxin causes a decrease in growth on the side of the stem exposed to light.
E) Removing the apical meristem enhances phototropism.