'Repine' means to express discontent or dissatisfaction, often in a low-level or fretful way. It describes the feeling of being unhappy with one's situation and complaining about it, though not necessarily in a loud or aggressive manner. 'Complain' is the correct answer as it directly relates to expressing dissatisfaction. The other options (Expand, Wish, Increase) don't relate to the meaning of expressing discontent.