In December 1991 under the leadership of which leader Russia, Ukraine and Belarus declared that the Soviet Union was disbanded.

Boris Yeltsin

The correct answer is Option (2) - Boris Yeltsin

In December 1991, under the leadership of Boris Yeltsin, Russia, Ukraine and Belarus, three major republics of the USSR, declared that the Soviet Union was disbanded. The Communist Party of the Soviet Union was banned. Capitalism and democracy were adopted as the bases for the post-Soviet republics.