Diction specifically refers to a speaker's choice of words and how "effective" these words are in achieving a specific goal.
So, your answer here should be B: Meaning and effect of words.
Google search "diction" if you want a definition.
I believe the correct answer is C.
Believe the best answer for this question would be D, "archetype." A femme fatale is a character who appears in many works of literature, although she takes on different forms. She possesses many of the same qualities and performs largely the same actions, making her an archetype. She may or may not be symbolic, solitary, or heroic, which means you can rule these options out as your answer because they are not definitive. Other examples of archetypes are the hero, the wicked witch, the wise old man, etc. Hope this helps.
A theme is an universal idea about life that the reader can relate to. A theme can always be applied to real life situations. So, the answer's D.