<span>D. Determined birdwatchers.
</span>
It is the main message or idea the author is trying to convey to the reader. The theme is the author's opinion of the subject.
No sorry but try reading it thoroughly that helps a lot :)
Https://prezi.com/m/km0trszxtyaq/historical-allusions-in-things-fall-apart/
The Wizard of Oz. It's the title of the book.