A market is in equilibrium when:

a. the quantity demanded equals the quantity supplied at the market price.

b. the horizontal axis crosses the vertical axis.

c. buyers don't want price to be any lower.

d. the equilibrium price is below the market price.

The correct answer is: a. the quantity demanded equals the quantity supplied at the market price.

When the market is at equilibrium, whatever is demanded by the consumers is equal to what the producers avail in the market. That is, when the demand is equal to the supply. When this happens, we say that the market is clearing since there are no surpluses nor shortages.