What Was Britain's Greatest Weakness at the Time of the Initial

What was Britain's greatest weakness at the time of the initial Nazi assault in 1940-1941?

A) British factories were unable to keep up with the German output of aircraft.
B) The Germans had cracked the British communication codes.
C) Britain relied on imports to feed its population.
D) The German military had primitive radar technology, whereas the British military
Did not.
E) Air battles were fought over German-held land where fallen planes were irretrievable.