The correct answer is: C. Arc method
The arc method is a way of calculating the price elasticity of demand by using two points on a demand curve. It is calculated by dividing the percentage change in quantity demanded by the percentage change in price.
The total outlay method is a way of calculating the price elasticity of demand by looking at the total amount of money spent on a good or service when the price changes. It is calculated by multiplying the price of a good or service by the quantity demanded.
The proportional method is a way of calculating the price elasticity of demand by looking at the percentage change in quantity demanded divided by the percentage change in price.
The geometrical method is a way of calculating the price elasticity of demand by looking at the slope of the demand curve.
The arc method is the most accurate way of calculating the price elasticity of demand because it takes into account the entire demand curve. The total outlay method, the proportional method, and the geometrical method are all less accurate because they do not take into account the entire demand curve.