What was the name of the cosmonaut who was stranded in space in 1991?

When the USSR was dissolved in 1991 there was much unfinished business: a giant country had broken up into smaller components, the form of government was not settled, property rights were unclear. Also, aspects of the future of the ambitious space programme had yet to be determined.

Sergei Konstantinovich Krikalev (born 27 August 1958) is a Russian mechanical engineer and former cosmonaut. He is a prominent rocket scientist, has completed six space flights and ranks third to Gennady Padalka and Yuri Malenchenko for the amount of time in space: 803 days, 9 hours, and 39 minutes. Krikalev had the misfortune to be on the space station Mir at the precise moment that the USSR disappeared on 26 December 1991.

On that date the space programme was taken over by the newly reconstituted Russian Federation. However, the Baikonur Cosmodrome and the landing site were located in the newly independent Kazakhstan. So, there was some uncertainty about the fate of Krikalev's mission. He remained in space twice as long as originally planned -- a total of 311 days – and finally returned to Earth on 25 March 1992. As a result, Sergei Krikalev is sometimes referred to as the "last Soviet citizen". These events are documented in the 1995 documentary "Out of the Present" by the filmmaker Andrei Ujică. Krikalev's story inspired the 2017 film "Sergio & Sergei", directed by Ernesto Daranas.

The other three answer options are all cosmonauts who died on 29 June 1971 during the re-entry of Soyuz 11.