The United Nations Secretary-General is appointed for a

The United Nations Secretary-General is appointed for a "five-year term". The Secretary-General is the head of the United Nations Secretariat, which is responsible for carrying out the day-to-day work of the United Nations. The Secretary-General is appointed by the General Assembly on the recommendation of the Security Council. The appointment is subject to the approval of the majority of the members of the General Assembly. The Secretary-General's term can be renewed for another five-year term. Therefore, the correct option to select in this scenario would be "five-year term".