The comma is after a kind of letter like Yes or No a sentence, so the answer would be B. Believe it or not Joe, it is for us to leave.
B - Sometimes Enaki is Enaki Narok, the Black God, is happy with us and blanketing the sky with dark clouds that pour out raig to nourish the plains.
This exceprt shows the connection between Enaki being happy and then sending the rain - this explains where the rain as well as droughts come from (when Enaki is unhappy)
I believe it would be D. ..
Its very hard to make a hook/intro without the basic outline/body
You don't have to worry about punctuation or spelling in a rough/first draft
You can always revise and make the tone more in with the subject.
First draft you would be mainly writing down all the information/ thoughts in your mind so you can look back and go through and decide whats more appropriate for your topic