Final answer:
The Germans' final attempt to defeat the Western Allies in Europe was during the Battle of the Bulge, when they launched a major offensive that was ultimately repelled by Allied forces.
Step-by-step explanation:
The Germans made their final attempt to defeat the Western Allies in Europe during the Battle of the Bulge. This last major offensive by the Germans was launched in December 1944 with the intent of capturing Antwerp, Belgium, to split Allied lines. Despite initial success in creating a 'bulge' in the Allied lines due to a surprise blitzkrieg attack, the Allies held firm, especially with the reinforcement of General George Patton's Third Army. After a grueling fight lasting until the end of January 1945, the Germans were repelled and suffered significant losses, diminishing their capacity to mount any further offensives, paving the way for the eventual Allied victory in Europe.
Therefore, the correct answer to the question is:
a) Battle of the Bulg