Which option best corrects the parallel structure in the following sentence We couldn't decide between Westerns a horror movie or to rent a romantic comedy.?

The best correction for the parallel structure in the sentence is: "We couldn't decide between Westerns, a Horror movie, or a romantic comedy." This revision ensures that all elements in the list are noun phrases, maintaining consistent grammatical structure. Additionally, adding a comma before "or" clarifies the separation between the items.