Some common features in Chopins writing is

A.

iambic pentameter and alliteration

B.

humor and farce

C.

irony and sex

(Kate Chopin/Comparing The Story of an Hour/The Storm)

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.