Why Were Americans Worried About Hitler's Attacks on Britain, in Particular

Why were Americans worried about Hitler's attacks on Britain, in particular?

A) America had an alliance with Britain that could force the nation into the war.
B) Many Americans had British ancestors or ties to businesses in Britain.
C) Many Americans still had family members living in Britain.
D) If Hitler took Britain, he would have access to an atom bomb.
E) If Hitler took Britain, he could use the British navy to attack the Americas.