The only preposition in the options available to you is of, so the correct answer is C.
A) and B) are conjunctions.
D) is an adverb.
It’s an adjective because it’s describing it
<span>The statement which is the best example of a theme in "Raymond's Run" is A. It is important to have confidence in oneself. Throughout this story readers can understand one very simple, but, at the same time very powerful truth of fellowship: we are stronger when we support each other and when we believe one in another. 'Believe in oneself' is the prominent idea of the book which leads to acknowledge that everyone is capable of being successful even when faced with great challenges.<span>
</span></span>
