If someone is interested in a career that gives them a relatively high earnings potential, the best choice would be "a career that has a relatively low supply and high demand for workers" (Option C).
Explanation: It is because when there is a low supply of a specific work and a high demand for workers, competition can be high which leads to relatively high earnings. The wage of supply tend to ascend because of the high salaries and in the same way, more workers enter the industry of that occupation.
The concept of demand for labor is a topic that says that the amount of demand for labor that an economy is willing to employ at a point in time.
The concept of labor supply states that it is the number of workers willing to take a specific job.