As a result of the second battle of the marne, germany

was ensured victory in the war.
was halted by the allies’ offensive.
forced the allies toward flanders.
won the spring offensive.

Germany was halted by the Allies' offensive.

Explanation:

The Battle was fought during World War I, and lasted from July 15 to August 6, 1918.

The French and British forces inhibitted the Germans' plan for a swift and decisive victory by the their offensive. After about hundred days later, the Germans' defeat culminated in the Armistice with Germany. The war became a stalemate when the Allied powers won the second battle of the Marne.   The Schlieffen plan by Germany was ruined and could not hope for a quick victory in France.

B, and I know this because I submitted it to a credible site and it read correct.