As a result of strikes in Canada the world price of nickel rose by 20 percent in December. Over the same period, the quantity demanded of nickel decreased from 10,000,000 to 8,500,000 pounds worldwide. The world price of nickel was 70 cents per pound before the strikes.

a. Show graphically the effect of Canadian strikes on the market for nickel.

b. Given the information above, what's the price elasticity of the world demand for nickel over the relevant price range? Interpret your answer.

c. Did the total expenditure for nickel increase, decrease, or remain constant after the strikes? How is this consistent with your answers to parts (a) and (b)? Explain clearly and concisely.