Blitzkrieg, literally "lightning war," was a Nazi military tactic. The basic idea was to shell with air support, puncture their defenses with artillery, and then encircle with infantry and other mobile units.
I believe the answer is: C. A form of war emphasizing quick movement to take an enemy off guard
This tactic is one of the most successful tactic that is used by nazi's army during the world war II. With this, Hitler and his army managed to capture Paris with very little casualties, which lead to the disaster that had to be faced by the British Army on Dunkirk.