সঠিক উত্তর হচ্ছে: UNTSO
ব্যাখ্যা: The first UN peacekeeping mission was established in May 1948, when the UN Security Council authorized the deployment of a small number of UN military observers to the Middle East to form the United Nations Truce Supervision Organization (UNTSO) to monitor the Armistice Agreement between Israel and its Arab neighbours.
Over the past 70 years, more than 1 million men and women have served under the UN flag in more than 70 UN peacekeeping operations. More than 100,000 military, police and civilian personnel from 125 countries currently serve in 13 peacekeeping operations.
Source: UNpeacekeeping.org