The Fact That We Observe Positively Sloped Market Labor Supply

Multiple Choice

The fact that we observe positively sloped market labor supply curves implies that

A) The substitution effect is stronger that the income effect for most workers
B) The income effect is stronger than the substitution effect for most workers
C) Most workers don't have income or substitution effects
D) The income effect plus substitution effect results in the positive slope
E) Labor laws require workers to work at least 40 hours per week