Answer: The presence of competition in free markets: Usually results in better quality and lower prices.
This is due to the free entry and exit from the market itself. The firm compete against each other in order to gain more control over the market by manipulating prices and supply of the commodity.
Under this , since there are no barrier it provides firm to enter a market and thereby sell their product alongside other competitors, i.e. now a consumer has a wide range of seller to choose from and also look for commodity with better quality.
Therefore the correct option in this case is (b)