The correct answer is option 'C': Several countries intervened to stop the massacre.

Explanation:

1. Massacre of Albanians:
The situation in question refers to the massacre of Albanians that occurred during the Kosovo War in the late 1990s. The conflict erupted between ethnic Albanian separatists, mainly represented by the Kosovo Liberation Army (KLA), and the Yugoslav government led by President Slobodan Milosevic. The Serbian forces, under Milosevic's command, engaged in a brutal campaign against the ethnic Albanian population in Kosovo.

2. International Intervention:
To address the humanitarian crisis and prevent further bloodshed, several countries intervened in the conflict. These interventions played a crucial role in putting an end to the massacre. Here are some key points regarding international intervention:

a. NATO's Involvement:
The North Atlantic Treaty Organization (NATO) played a significant role in stopping the massacre. NATO countries, led by the United States, launched a military intervention against Yugoslavia in March 1999. The NATO airstrikes targeted Serbian military installations and infrastructure, aiming to halt the ethnic cleansing and create conditions for a diplomatic solution.

b. Diplomatic Efforts:
In parallel with the military intervention, diplomatic efforts were made to resolve the conflict. The Contact Group, consisting of representatives from the United States, Russia, the United Kingdom, France, Germany, and Italy, initiated negotiations between the parties involved. These diplomatic efforts eventually led to the signing of the Kumanovo Agreement in June 1999, which ended the conflict and set the stage for the withdrawal of Serbian forces from Kosovo.

c. United Nations Involvement:
The United Nations (UN) also played a crucial role in halting the massacre. The UN Security Council passed Resolution 1244, which authorized the establishment of an international civil and security presence in Kosovo (UNMIK) and the deployment of NATO-led peacekeeping forces (KFOR). This international presence helped maintain stability and protect the Albanian population from further attacks.

d. Humanitarian Aid:
During and after the conflict, several countries provided humanitarian aid to the affected Albanian population. This assistance included food, shelter, medical supplies, and support for displaced persons. Humanitarian organizations, such as the United Nations High Commissioner for Refugees (UNHCR), played a vital role in coordinating these efforts.

3. Conclusion:
In summary, it was the collective intervention of several countries, led by NATO, diplomatic negotiations, and the establishment of international security forces that forced the Albanians to stop the massacre. These actions aimed to protect the Albanian population, restore stability, and bring an end to the conflict in Kosovo.

Option 'c' is correct