Market Power is a term which specifically refers to D.) The ability of a firm to set its price above marginal cost.

The market power is the ability of a firm to set a higher price than the marginal costs without incurring losses. These firms are known to be price-makers. They control the market price of the product. One example of a firm with market power is a monopolist. A monopolist firm is the only seller supplying products with no close substitutes. It has high market power because it has no competition and the demand remains the same even with an increase in price.

Option A is known as the bargaining power of suppliers. It is a business strategy that depends on the type of market and economic conditions. Option B is known as the invisible hand. Invisible hand tells us that a market will move to equilibrium based on the efforts of the people and with no interventions with the government.