Who was the Tsarina married to Nicholas II and played a significant role in the government's affairs while he was at the front?

The correct answer is Tsarina Alexandra, who was married to Nicholas II. During World War I, while Nicholas was at the front leading the Russian army, Alexandra took on a significant role in managing the government and addressing issues at home. Her influence grew during this period, particularly as she was left in charge of the empire, which was already experiencing profound social and political turmoil.

Alexandra's involvement in state affairs was compounded by her reliance on Grigori Rasputin, a controversial figure whose presence further alienated the royal family from the populace and the governing classes. The public perception of Alexandra, as a foreign-born princess and a strong supporter of Rasputin, fueled discontent and contributed to the eventual collapse of the tsarist regime.

Maria Feodorovna was Nicholas II's mother and did not play a direct role in government affairs during this time, while Empress Catherine refers to Catherine the Great, a prominent historical figure but not relevant to this particular context.