Which of the Following Explains the "Beauty Premium" Differences in Wages

Which of the following explains the "beauty premium" differences in wages?

A) Better-looking people are preferred by customers; thus, employers will pay them higher wages than average-looking people.
B) People who project an attractive personal appearance may be more intelligent than average-looking people; thus, employers will pay them higher wages than average-looking people.
C) Average-looking people are preferred by customers; thus, employers will pay them higher wages than better-looking people.
D) Both a and b are correct.