AP Microeconomics

Answer - D - All of the above are reasons that the labor curve might shift.

Key Takeaway: Generally, as the overall level of wages increases, more labor will be offered up for sale, as more people will be willing to work for the offered wages. This means that the majority of the time, there is an upward sloping labor supply curve. Three main reasons that the labor supply curve might shift are immigration, a change in tastes or cultural norms (like women joining the workforce), and opportunities that are available in other competing labor markets.