Market Equilibrium:
Market equilibrium is a state of balance in a market where the quantity demanded by consumers is equal to the quantity supplied by producers. In other words, it is the point at which the demand and supply curves intersect, and there is no excess demand or excess supply in the market. When a market is in equilibrium, there is no pressure for prices to change, and both buyers and sellers are satisfied.

Explanation:
The correct answer to the given question is option C, which states that market demand equals market supply. Let's understand why this is the correct answer:

Market Demand:
Market demand refers to the total quantity of a product or service that consumers are willing and able to purchase at a given price during a specific period. It is determined by various factors such as price, income, tastes and preferences, and the availability of substitutes. The market demand curve is downward sloping, indicating that as the price of a product decreases, the quantity demanded increases, ceteris paribus.

Market Supply:
Market supply refers to the total quantity of a product or service that producers are willing and able to offer for sale at a given price during a specific period. It is determined by factors such as the cost of production, technology, resource availability, and government policies. The market supply curve is upward sloping, indicating that as the price of a product increases, the quantity supplied also increases, ceteris paribus.

Market Equilibrium:
Market equilibrium occurs when the quantity demanded by consumers is equal to the quantity supplied by producers at a specific price. At this point, there is no excess demand or excess supply in the market. The equilibrium price, also known as the market clearing price, is the price at which the quantity demanded equals the quantity supplied. It is determined by the intersection of the demand and supply curves.

Visual Representation:
To visually represent market equilibrium, we can draw a graph with price on the y-axis and quantity on the x-axis. The demand curve slopes downwards, while the supply curve slopes upwards. The point where these two curves intersect represents the equilibrium price and quantity.

Conclusion:
In conclusion, market equilibrium is a state of balance in a market where the quantity demanded equals the quantity supplied. It is the point at which the demand and supply curves intersect, and there is no excess demand or excess supply. Market equilibrium is an important concept in economics as it helps to determine the market price and quantity of a product or service.