I would go with C makes the most sense to me
The common themes that Romantic period, the victorian age, and the modern era is a theme about revolution and democracy. In the romantic period, characters have a romance like story but the revolt still circles in the storyline, it is same with the victorian age and modern era where the fight for democracy is being the center of the story.
The following that is a modifier is C, an adjective and an adverb.
