As the most basic way for the ego to defend against being overwhelmed, is the psychological process in freud's theory that protects an individual from experiencing extreme anxiety or guilt by pushing ideas out of conscious awareness and into the unconscious.

steady state because it the only on that maes sense

out of the choices i'd say d the ability to set goals, mainly because to desire to continue you need motivation but it isn't motivation in that part, but setting goals means you have an endgame and you want to reach it which sums up motivation.