Final answer:
Herbert Spencer is the theorist who claimed that individuals rise to their proper level in society based on a belief in meritocracy.
Step-by-step explanation:
The theorist who claimed that people rise to their proper level in society based solely on their belief in a meritocracy is Herbert Spencer. Spencer was a British sociologist and philosopher associated with the social Darwinism theory, which posits that the principles of natural selection and survival of the fittest apply to human societies. Although Karl Marx and Max Weber are famous sociologists, it was Herbert Spencer who was most closely related to the idea that in a meritocracy, individuals achieve status based on their ability and hard work rather than ascribed status or privilege.