What made germany’s invasions of europe difficult to stop during world war ii?

What made Germany’s invasions of Europe difficult to stop during World War II?

A) Germany’s bombs and torpedoes

B) Germany’s powerful U-boats

C)Germany’s air attacks and fast-moving ground troops

D) Germany’s fast-moving sea attacks and powerful navy

You'er answer is

C) Germany's air attacks and fast-moving grounds troops

Hope this helps!!!

there has only been 12 presidents. the 12th president is/was moon jae-in