Option 1: objector -> A synonym of dissident; someone who expresses disagreement or opposition.
Option 2: rebel -> A synonym of dissident; someone who resists authority or control.
Option 3: subversive -> A synonym of dissident; someone who seeks to undermine established systems.
Option 4: conformist -> Someone who complies with accepted rules and standards; opposite of dissident.
Hence, Option 4: conformist -> A dissident is someone who opposes or disagrees with established authority or beliefs, while a conformist is someone who follows and accepts established norms and conventions. They are opposite in meaning. -> correct