His appointment was confirmed last month.

Answer: Option D

Appointment : an arrangement to meet someone at a particular time and place.
Disappointment : sadness or displeasure caused by the non-fulfilment of one's hopes or expectations.
Discharge : tell (someone) officially that they can or must leave a place or situation.
Suspension : the action of suspending someone or something or the condition of being suspended.
Dismissal : the act of ordering or allowing someone to leave.

Antonym of Appointment is Dismissal