Rhea is an employee at Diaz Inc. She specializes in graphic and web design, user interface design, and search engine optimization. She also knows how to interact with customers by asking them about their preferences and providing them with products that meet their needs. Which of the following statements is true about Rhea? A. She specializes in outsourcing. B. She is a part of the external labor market. C. She bases her work on the terms of a psychological contract. D. She is an on-call worker. E. She is a knowledge worker.