Option 1: Inhibit -> means to restrain or hold back, which relates to preventing expression but not the direct opposite.
Option 2: Release -> means to let out or free, which is actually a synonym of vent, not an opposite.
Option 3: Deliberate -> means intentional or to think carefully, which is unrelated to the meaning of vent.
Option 4: Conceal -> means to hide or keep secret, which is the direct opposite of venting (expressing openly).
Hence, Option 4: Conceal -> To vent means to express or release emotions/feelings openly, while to conceal means to hide or keep something secret. These are direct opposites in meaning. -> correct