When did the USSR formally disintegrates into 15 republics?

Answer: Option A

In 1991 the USSR formally disintegrates into 15 republics. In the decades after it was established, the Russian-dominated Soviet Union grew into one of the world’s most powerful and influential states and eventually encompassed 15 republics–Russia, Ukraine, Georgia, Belorussia, Uzbekistan, Armenia, Azerbaijan, Kazakhstan, Kyrgyzstan, Moldova, Turkmenistan, Tajikistan, Latvia, Lithuania, and Estonia. In 1991, the Soviet Union was dissolved following the collapse of its communist government.