Answer: The correct answer is "Identity".
Explanation:
Multiple theorists in social sciences have proposed that individuals create their identity based on several factors. One of those factors is the identification with the social groups that they associate with.
Those groups play an important role in the sense of identity of certain individuals, as they use them as a reference group.
In this particular case, ethan clearly identifies with Phi Theta Kappa in all of the actions presented in the text.
All of the actions serve to reinforce Ethan's identity with regard to the Phi Theta Kappa group.