A Predicate Nominative is a word that describes or identifies the subject.
In this case, Dark would describe the dog as being dark, and identifying it as a dark dog.
So the answer is A, dark.
The words "he," "she," "it," or "they" are used in this point of view. This point of view can either be omniscient where the reader knows what all the characters are doing in the story or it can be limited to having the reader only know what is happening to one specific character.
The answer is the author was Moses. This is because Moses did not live at the time of Job which makes is not correct.
Hope this helps!!