What was the main reason for Russia's starting of war against Ukraine?

The correct answer is Option (1) → The intention of Ukraine to join NATO

Russia began its full-scale invasion of Ukraine on 24 February 2022. The main reason it gave was Ukraine’s wish to join NATO (the North Atlantic Treaty Organization), the Western military alliance. NATO had said in 2008 that Ukraine would one day become a member, and in 2019 Ukraine wrote the aim of joining NATO and the European Union into its constitution. Russia saw NATO’s spread up to its own border as a threat to its security and, before the war, demanded a guarantee that Ukraine would never join.

Note: This ‘current affairs’ question is about events more than four years before this May 2026 paper. NTA’s current affairs calendar still seems to be set to early 2022.