The correct answer to which of the mentioned categories is not a demographic classification is personality.
Demograpy deals with the statistical study of populations, bearing in mind its flow in time and space, the size and structure, mobility etc. In order to acrry demographic analysis, different categories conveying crucial information are employed such as education, ethnicity, nationality, religious beliefs or some of the mentioned in the question age, gender and race. These categories allow to study behaviours, the size and structuring of communities.
On the other hand, personality is not a demographic classification since it is too abstract, unstable and cannot be meassured in (social) scientific terms.