Possible Clues:

• Letters that often precede a Ph.D
• College sr.'s test, often
• Hurdle for an M.A. seeker
• MA seeker's test
• Test for Ph.D. hopefuls
• Exam for college seniors
• Test for univ. seniors
• Test taken by some college seniors
• Master's seeker's hurdle, for short
• Ph.D. hopeful's exam