To Understand How Plant Phototropic Responses Are Regulated, a Researcher

To understand how plant phototropic responses are regulated, a researcher performed the following experiment. He exposed oat seedlings to light and then cut off tips of coleoptiles and placed them on agar blocks. Later, the agar blocks were placed on decapitated coleoptiles of other individuals. Some seedlings were kept in darkness, while others were exposed to light. Based on your knowledge of auxin synthesis and mode of action, predict in what cases the decapitated coleoptiles would bend to the right.

A) when the block was placed on the right side of the coleoptiles in both dark and light treatments
B) when the block was placed on the left side of the coleoptiles in both dark and light treatments
C) as long as light was coming from the right, decapitated coleoptiles bent to the right independently of agar block placement
D) when the block was placed on the left side of the coleoptiles in dark only
E) when the block was placed on the right side of the coleoptiles in dark only