at the market equilibrium price, \na. everyone can buy the product.\nb. demand equals supply.\nc. quantity…

Brief Explanations:

Market equilibrium occurs when the quantity that consumers are willing and able to buy (quantity demanded) is exactly the same as the quantity that producers are willing and able to sell (quantity supplied). It's not about everyone being able to buy the product (A is wrong as there may be budget - constraints), demand and supply are different from quantity demanded and quantity supplied (B is wrong), and quantity and price are not equal concepts (C is wrong).

Answer:

D. quantity demanded equals quantity supplied.