At the equilibrium price,

1. Analyze the question The question asks what is true at the equilibrium price. This is a basic market theory question about demand and supply.

2. Explain the concept

• Demand is the quantity of a good consumers are willing and able to buy at each price.
• Supply is the quantity of a good producers are willing and able to sell at each price.
• Equilibrium price is the price at which the market "clears". The quantity demanded equals the quantity supplied, so there is no shortage and no surplus, and no pressure for the price to change.

3. Step-by-step solution

• If demand is greater than supply, there is a shortage (excess demand). Price tends to rise, so the market is not in equilibrium. This rules out D.
• If demand is less than supply, there is a surplus (excess supply). Price tends to fall, so the market is not in equilibrium. This rules out C.
• B ("price equals demand only") makes no economic sense. Price is not "equal" to demand, and equilibrium involves both demand and supply, not demand alone.
• A says demand equals supply. This is the definition of equilibrium: Qd = Qs.

4. Answer The correct option is A. demand equates supply.

5. Exam tip Remember the pattern:

• Qd > Qs → shortage, price rises
• Qd < Qs → surplus, price falls
• Qd = Qs → equilibrium, price is stable

In the exam, any option that says "equilibrium" together with "equal" quantities of demand and supply is almost always correct.