How do I analyze this case utilizing the I.R.A.C. method?

Case #2 Leonard A. Vernon ("Vernon"), a citizen of the United States, is a black male over 40 years old who was born in Belize. He received a B.A. in Civil Engineering in 1977 and an M.S, in Environmental Engineering in 1980. In January 1984, The Port Authority of New York and New Jersey ("Port Authority") hired Vernon to be a Principal Administrative Assistant, a Level B-92 position, with the Civil and Environmental Unit of the Engineering Department. In January 1985, Vernon was promoted to Staff Services Engineer, a Level B-93 position. Throughout his career at Port Authority, Vernon has been recognized favorably for his work. In September 1989, Heidi Rosenberg, a white engineer in the Environmental Engineering Unit, was promoted to Senior Engineer, a Level B-94 position. Vernon was not promoted despite the fact that Marvin Krishner, Chief Environmental Engineer of the unit and Vernon's immediate supervisor, wrote in a 1987 memorandum that Rosenberg and Vernon were both "performing at 'Senior Levels." In December 1992, Rosenberg informed her supervisor that she had received an employment offer in another department, and to induce her to stay in the Environmental Engineering Unit, she was promoted to Supervising Environmental Engineer, a Level B-95 position. In March 1993, Rosenberg resigned from Port Authority, and Port Authority advertised her position internally as well as externally. Vernon applied for the B-95 position but was notified in May that he had not been selected for the position. A white, 65-year-old temporary employee, who had been working for Port Authority for one year, filled the vacancy. In March and August of 1994, Vernon complained to the Assistant Chief Engineer for Design and the Executive Director of Port Authority about alleged ongoing discriminatory practices at Port Authority. In September 1994, Frederick Meyers, Manager of Port Authority's Equal Employment Office ("EEO"), started an investigation into Vernon's allegations of discrimination. Question: Was race a factor in the Port Authority's denial of Vernon's promotion? Explain