The correct answer is B) peaceful.
The term that best describes the break up of the Soviet Union is peaceful. This event ocurred over several months.
Russian leader Mikhail Gorbachev generated the reforms called “Perestroika” that motivated the break up of the Soviet Union. Those reforms changed the life in Russia during 1990-1991. Among the important results of the Perestroika was to bring democratic institutions to Russia and decentralized its economy. This also resulted in the downfall of the Soviet Union in a peaceful way. For this actions, in 1990 Gorbachev was awarded the Nobel Prize for Peace.