A 27-Year-Old Graduate Student Finds Out That He Failed His

A 27-year-old graduate student finds out that he failed his comprehensive exams, an experience that would normally be extremely anxiety-provoking. However, instead of becoming openly upset, he goes out drinking with his friends that night and never even mentions the failure. Even the next day, he doesn't actually act like anything has gone wrong with his career. Vaillant would classify this as an example of a(n) :

A) identity vs. identity diffusion crisis.
B) self-actualization threat.
C) insecure attachment style.
D) immature defense mechanism.