The correct option is C Armistice
'The cessation of warfare before a treaty is signed' is Option C, 'Armistice'. Option A, 'Affidavit' is a written statement confirmed by oath or affirmation and can be used as proof in court. Option B, 'Agreement' is a legal joint decision between two or more parties that a particular course of action should be taken . Option D, 'Amnesty' is a decision by government that allows political prisoners to go free. Thus, options A, B and D are incorrect and the correct word for the given phrase is Option C, Armistice.