Which of the following statements is correct?
a. If a firm decreases the price of its product and demand for the good is inelastic, its total revenue will decrease.
b. If a firm decreases the price of its product and demand for the good is elastic, its total revenue will decrease.
c. As the price of X falls and we move down an individual's demand curve for X, the money income of the individual also changes.
d. The own price elasticity of demand is constant at all points along a linear demand curve.