Step 1: "Relinquish" means to give up or surrender something. Step 2: The opposite of "relinquish" is "possess," which means to own or retain something. Step 3: "Abdicate" and "renounce" are related to giving up power or position, which can be a type of relinquishing, but they are not the direct opposite. "Deny" does not fit in this context.
Thus, the correct answer is "possess."