10. Consumer the aggregate (economy-wide) PPF illustrated below. y 20 PPF X 10 If all consumers in the economy have identical Cobb-Douglas preferences, then which of the following statements is true? a. px = py = $1 could be equilibrium prices in this economy. b. px = $2 and py = $1 could be equilibrium prices in this economy. C. px = $1 and py= $2 could be equilibrium prices in this economy. d. px = $2 and py = $4 could be equilibrium prices in this economy. Both c) and d) are true. e.