An Upward-Sloping Individual Labor Supply Curve Indicates That the

Multiple Choice

An upward-sloping individual labor supply curve indicates that the

A) income and substitution effects are of roughly equal strength.
B) substitution effect is the only effect at work.
C) income effect is the only effect at work.
D) income effect is stronger than the substitution effect.
E) substitution effect is stronger than the income effect.