Demand Curves Slope Downward Because

Multiple Choice

Demand curves slope downward because

A) the substitution effect, which is always positive, dominates or reinforces the income effect.
B) the substitution effect, which is always negative, dominates or reinforces the income effect.
C) the income effect, which is always positive, dominates or reinforces the substitution effect.
D) the income effect, which is always negative, dominates or reinforces the substitution effect.