The table gives the price of a good together with the total expenditure on that good for certain periods while the market is in equilibrium. Period 1: price $12$, total expenditure $96\,000$. Period 2: price $5$, total expenditure $40\,000$. Period 3: price $8$, total expenditure $64\,000$. Period 4: price $10$, total expenditure $80\,000$. Period 5: price $4$, total expenditure $32\,000$. What conclusion can be drawn from these figures?
- AThe good has constant opportunity cost.
- BThe good is an inferior good.
- CThe price elasticity of demand is equal to one.
- DThe price elasticity of supply is equal to zero.