Option 1: Abandon -> means to give up or leave behind, similar to relinquish, not opposite.
Option 2: Exempt -> means to free from an obligation, not the opposite of giving up possession.
Option 3: Deny -> means to refuse or reject, not directly opposite to relinquish.
Option 4: Retain -> means to keep or hold onto something.
Hence, Option 4: Retain -> Relinquish means to voluntarily give up or surrender something, while retain means to keep or continue holding onto something. These words represent opposite actions regarding possession or control. -> correct