The answer is B, Suppression. Suppression is a ‘mature’ defense mechanism wherein a person ignores an unwanted impulse or feeling in order to accomplish a task, effectively putting that impulse or feeling away when necessary. This is a conscious act. Repression, on the other hand, is not conscious, and the impulse or feeling is unconsciously ignored at all times. Altruism is doing service for others for primary gain, or a feeling of joy or satisfaction. Sublimation is taking an unwanted or unacceptable impulse or feeling and channeling it into something acceptable to society. For example, someone who has a desire to engage in violence becomes a boxer.

Publication reference : Vaillant GE. Involuntary coping mechanisms: a psychodynamic perspective. Dialogues in Clinical Neuroscience. 2011;13(3):366-370.
Reference URL: https://www.ncb.nlm.nih.gov/pmc/articles/PMC3182012/