Some common features in Chopin's writing is C. irony and sex.
It's not A because Chopin primarily wrote prose, and iambic pentameter is usually found in poetry. It's not B because her writing is usually rather depressing and oppressive towards the female sex. So based on this, I'd go with C as the correct answer. Her writing has some sexual scenes which were considered inappropriate for the period (especially The Storm), and irony is omnipresent in The Story of an Hour.