4. In each of the following scenarios, state whether the labor supply curve would shift to the left, to the right, not shift at all, or if the shift is ambiguous because there is more than one effect and they would move the curve in opposite directions.

a. The stock market rises sharply.

b. Fewer teenagers work while in school than before.

c. A large fraction of the population flees the country because of a bird flu epidemic.

d. The expected future wage declines and the stock market crashes.

e. The current real wage rate rises.