The rebels returned home under an amnesty.

Answer: Option A

Pardon : the action of forgiving or being forgiven for an error or offence.
Assistance : the action of helping someone by sharing work.
Security : the state of being free from danger or threat.
Judicial : of, by, or appropriate to a law court or judge; relating to the administration of justice.
Amnesty : an official pardon for people who have been convicted of political offences.

Synonym of Amnesty is Pardon