Concept:Higher wages change the balance between work and leisure, causing a long-run reduction in labour supply.
Explanation:When wages rise, workers earn more income for the same amount of work.
With higher income, people treat leisure as a normal good and want more of it.
As workers choose more leisure, they are willing to work fewer hours.
Thus, the quantity of labour supplied falls in the long run.
This happens because the income effect becomes stronger than the substitution effect over time.
Answer:D. supply of labour to decrease