Which of the Following Alternatives Best Represents the Sequence of Events

Which of the following alternatives best represents the sequence of events by which melatonin is secreted in the blood?

A) suprachiasmatic nucleus $\rightarrow$ pineal gland $\rightarrow$ melatonin
B) pineal gland $\rightarrow$ suprachiasmatic nucleus $\rightarrow$ melatonin
C) suprachiasmatic nucleus + pineal gland $\rightarrow$ melatonin
D) suprachiasmatic nucleus $\rightarrow$ pituitary gland $\rightarrow$ melatonin