On 28 January 1871 the Government of National Defence based in Paris negotiated an armistice with the Prussians. With Paris starving, and Gambetta's provincial armies reeling from one disaster after another, French foreign minister Favre went to Versailles on 24 January to discuss peace terms with Bismarck. Bismarck agreed to end the siege and allow food convoys to immediately enter Paris (including trains carrying millions of German army rations), on condition that the Government of National Defence surrender several key fortresses outside Paris to the Prussians. Without the forts, the French Army would no longer be able to defend Paris.

Answer this question, if possible (if impossible, reply "unanswerable"): On what date did the Government of National Defence negotiate an armistice?
28 January 1871