Other Things Equal,who of the Following Would Not Tend to Earn

Other things equal,who of the following would not tend to earn more?

A) Someone in a riskier or more unpleasant job, rather than a safer or more pleasant job.
B) Someone in a job that requires a graduate degree rather than an undergraduate degree.
C) Someone who works longer hours, rather than shorter hours.
D) All of the above would tend to earn more.