Dean Williams' sister's first name in the 2021 The Wonder Years is Kim.
Kim Williams is Dean's sister in ABC's 2021 reimagining of The Wonder Years. Laura Kariuki portrays Kim, making her part of the Williams family at the center of the series. The show follows 12-year-old Dean as he grows up in Montgomery, Alabama, during the late 1960s.
The 2021 series is not a continuation of Kevin Arnold's family story. It uses a new Black middle-class family and a different narrator: adult Dean is voiced by Don Cheadle. Kim is therefore distinct from Karen Arnold, the older sister in the 1988 original.
The names in the answer choices can cause confusion because Lillian is Dean's mother, while Keisa is Dean's friend and crush. Charlene is a recurring character, not Dean's sister.