Explanation:

Certainly! Let's analyze the total expenditure method and the options given:

- Total Expenditure Method: It studies how total revenue (price times quantity demanded) changes as price changes to determine elasticity.

- Ed = 1 (Unitary Elastic): Total expenditure remains unchanged when the price changes. A 1% price change results in a 1% change in quantity demanded.

- Ed < 1 (Inelastic Demand): Total expenditure decreases as price decreases and increases as price increases. Quantity demanded changes by a smaller percentage than the price change.

- Ed > 1 (Elastic Demand): Total expenditure increases as price decreases and decreases as price increases. Quantity demanded changes by a greater percentage than the price change.

- Ed = 0 (Perfectly Inelastic): Demand does not change with price changes. Total expenditure is independent of price changes.