Carol is one of Lori's schoolmates. It is mentioned that she beat Lori for homecoming queen.
Her first 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.
In "Selfie Improvement", Lori finds out that Carol's selfies are getting more likes than hers, and spends most of the episode trying to take a photo of herself to outdo Carol's. In the end, Lori ultimately realizes she shouldn't have obsessed over trying to compete with Carol and admits defeat to her. Carol, however, replies that she herself has always envied Lori, and the two become friends.
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.
In "Selfie Improvement", when Lori was about to return the stuff she bought at a store to compete with Carol, she spots her shopping in the same store and catches up with her. Lori apologized to Carol for competing with her and admit that Carol is better than her. Carol, a second later, said that of the exact opposite of what Lori admitted. Carol admits that she is jealous of Lori's golf skills and closeness with her siblings. After that, Lori and Carol become close friends, especially since they compete with another duo of best friends together. Carol is actually a kind and insecure girl, not that different from her now friend, Lori.
Carol has a striking resemblance to Lori, except she has longer blonde hair that points to her right side; she wears a blue headband, a blue shirt with a white collar, a brown skirt with a checker pattern, and brown shoes with purplish-blue socks worn high as shown in "Picture Perfect". She gets a recolor in "Selfie Improvement", with her shirt, socks, eyeshadow, and headband now being purple.