Consider the log-log model for estimating the price elasticity of demand for a product: log (Q) = a + a, * log(P) + E where Q represents the quantity demanded and P represents the price of the product. Which of the following statements correctly describes the interpretation of the coefficient a, in this model? O a. a, represents the price elasticity of demand, indicating the change in quantity demanded for a one-percent increase in price. O b. a, represents the expected percentage change in quantity demanded for a one-unit increase in price. Oca, represents the expected change in quantity demanded for a one-unit increase in price. O da, represents the price elasticity of demand, indicating the percentage change in quantity demanded for a one-percent increase in price.