Carol is one of Lori's schoolmates. It is mentioned that she beat Lori for homecoming queen.
Her first and only appearance was in "Picture Perfect", where Lincoln tries to coerce Lori into being a part of his revised family portrait by threatening to replace her with Carol, due to her looking similar to Lori. Lincoln invited Carol and opened the door so Lori could see her while they talk. Outraged, Lori slammed the door in front of Carol's face, much to the latter's surprise.
She was possibly mentioned by Lori, during a phone conversation, in "Spell It Out", "Job Insecurity", and "Change of Heart". Although it's unclear if she meant the same Carol, the possibility is very high that this was the Carol she was referring to.
She will be prominently featured in the upcoming episode "Selfie Improvement", where a photo of her gets more "likes" than Lori, causing the latter to try to beat her at her own game.
Not much known is about her except that she's Lori's rival, and defeated her as homecoming queen. She seems to like being better than Lori, or annoy her, as she agreed to replace Lori in Lincoln's family picture.
In "Spell It Out", Lori mentions that Carol was acting superior to her friends after getting eyelash extensions. Although it's unclear if she meant the same Carol, the possibility is very high that this was the Carol she was referring to.
Carol looks nearly identical to Lori, except she has longer blonde hair that points to her right side; she wears a blue headband, a blue shirt with white collars, brown skirt with a checker pattern, and brown shoes, with purplish-blue socks worn high.