Answer:
D. develop core competencies and maybe a distinctive competence that rivals don't have or can't quite match and that are instrumental in helping it deliver attractive value to customers.
Explanation: Competitive advantage is term which describes an organisation's capacity to outperform it's rivals or competitors through the efficient use of resources, Economies of scale, reduced price ,quality of products or services.
A firm with a good Competitive advantage has the capacity to generate revenue and profit in order to sustain its market share and values.
FOR A FIRM TO HAVE A COMPETITIVE ADVANTAGE OVER ANOTHER FIRM, IT MUST HAVE CORE COMPETENCE THAT THE RIVALS DO NOT HAVE, AND THIS COMPETENCE MUST BE ATTRACTIVE TO CUSTOMERS.