The correct option is D accused
Exonerate means to absolve (someone) from blame for a fault or wrongdoing The opposite of exonerated is accused, or to charge (someone) with an offence or crime. Hence, Option D is correct. Among the rest of the options, imprisoned means kept in prison, complained means express dissatisfaction or annoyance about something, expelled means officially made (someone) leave a school or other organization. These do not express the antonym, hence incorrect.