The correct answer is - A. each nation desires an independent sovereign state.
It is very rare that a multinational state can function without any ethic or separatist problems. Most of the ethnic groups want to have their own independent state and not be ruled by someone else from another ethnic background. There lots of examples of this throughout the world, like Spain, were the Catalans in the northeastern part of the country, and the Basques in the northern part of the country, have strong separatist movements, and have been trying for decades to become independent states.