Sammy, a 9-year-old girl, is overweight. She is constantly teased and tormented by other children in school. Her parents try to cheer her up by telling her that they were also overweight when they were young and even now they are overweight but they don't worry about what others say about them. Based on the given information, which of the following is the primary cause for Sammy being overweight?
a. Sammy spends most of her day playing on her computer.
b. Sammy's meal times are irregular.
c. Sammy does not exercise as regularly as her parents.
d. Sammy's parents are overweight.