How does 'quantity supplied' differ from 'quantity demanded'?

• A. Quantity supplied is always greater than quantity demanded.
• B. Quantity supplied and quantity demanded are the same concept.
• C. Quantity supplied refers to the amount consumers are willing to buy, while quantity demanded refers to the amount sellers are willing to produce.
• D. Quantity supplied refers to the amount sellers are willing to produce, while quantity demanded refers to the amount consumers are willing to buy.

Answer: (D)