Who were the primary combatants in the Battle of Passchendaele?

The Battle of Passchendaele, which took place during World War I from July to November 1917, primarily involved the Allies and the Central Powers. The Allies, consisting mainly of British and Commonwealth troops, aimed to achieve a breakthrough to secure the coast and disrupt German supply lines. Conversely, the Central Powers, primarily Germany, were defending their positions against this offensive. This battle is notable for the horrific conditions, including extensive mud and waterlogged terrain, which affected both tactics and outcomes. The incredible human cost and the tactical failure to achieve significant gains exemplify the challenges faced during this warfare. Understanding this context highlights the significance of the battle within the larger strategic efforts of the war. The other options correctly involve forces from different contexts or timeframes that did not participate in this specific battle.