Final answer:
The source of a firm's competitive advantage is its core competencies and resources.
Step-by-step explanation:
The correct answer is 4) Core competencies, resources, competitive advantage.
A firm's core competencies are its unique strengths or abilities that differentiate it from competitors. These core competencies are developed from the firm's resources, which include tangible assets like equipment and structures, as well as intangible assets like knowledge and expertise. By leveraging its core competencies and resources effectively, a firm can gain a competitive advantage in the market.