(a) Draw a production possibility frontier, clearly marking the regions of inefficient production, efficient production and unattainable production. (3 marks) (b) Illustrate how the slope of the PPF represents opportunity cost. Why is the frontier concave to origin? (4 marks) (c) Making use of demand and supply diagrams, illustrate the likely effect on equilibrium price and quantity of each of the following events: (i) wind-surf board manufacturers discover a cheaper material with which to make the boards; (2 marks) (ii) a number of accidents at seaside resorts reduces the popularity of wind-surfing; (2 marks) (iii) the government places an additional sales tax on wind-surf boards. (2 marks)