What is the best definition of a "blitzkrieg"?

The German military tactic called blitzkrieg is one of the most, if not the most famous one from the World War II. This tactic was basically consisted of a quick, surprise attack by using the locally concentrated firepower and the mobile forces in combination. The purpose of this tactic was to cause panic and disorganize the army of the opponent, and in most cases it did its job properly, with the majority of this type of attacks being successful, resulting in German occupation of numerous territories across Europe.

Answer:B. Rapid invasion by air and land