The German Schlieffen plan called for

AA quick invasion of Russia so that the war would only be fought on one front
BA blockade of France to start that country into submission
CA swift knockout of France, combined with defensive action against Russia
DSimultaneous invasions of France, Britain, and Russia with heavy reliance on the navy

Verified Answer :

The German Schlieffen plan called for "c. A swift knockout of France, combined with defensive action against Russia," since the idea was to both expand and protect territory simultaneously.