Price elasticity of supply measures the responsiveness of quantity supplied to

Step 1: Analyze the question The question asks what price elasticity of supply responds to. The key words are "price" and "supply."

Step 2: Explain the concept Price elasticity of supply (PES) measures how much the quantity supplied of a good changes when the price of that same good changes.

Formula:

PES = % change in quantity supplied ÷ % change in price

• If PES > 1, supply is elastic (suppliers respond strongly to price changes).
• If PES < 1, supply is inelastic.
• If PES = 1, supply is unitary elastic.

Step 3: Check each option

• A. A change in the demand for the product: Wrong. A change in demand shifts the demand curve and is not what PES measures.
• B. A change in the price of the commodity: Correct. This is the definition of PES.
• C. Changes in consumers: Wrong. This relates to demand factors such as population or tastes.
• D. Changes in prices of other commodities: Wrong. This describes cross elasticity (of demand or supply), not price elasticity of supply.
• E. Changes in suppliers' income: Wrong. This is not a measure used in elasticity of supply. Income elasticity relates to demand.

Step 4: Answer

Tip: Look at the name of the elasticity. "Price elasticity of supply" means quantity supplied responding to the price of that same good. Whenever you see "other commodities," think cross elasticity. Whenever you see "income," think income elasticity.