The boy was accused of theft.

Answer: Option C

Accused : a person or group of people who are charged with or on trial for a crime.
Liberated : (of a place or people) freed from enemy occupation.
Impeached : call into question the integrity or validity of (a practice).
Exonerated : (of an official body) absolve (someone) from blame for a fault or wrongdoing.
Sentenced : declare the punishment decided for (an offender).

Antonym of Accused is Exonerated