Ais typically defined as two or more independent clauses joined without a punctuation mark or coordinating conjunction.
a. complex-compound sentence
b. sentence fragment
c. run-on sentence
d. compound sentence

are you asking for an essay and whats the story?

lets none because you provide no details.

well, number 1, the 1920s was not economically prosperous until the start of the lend-lease act, which employed large amounts of people in producing equipment for the allies.

b. world war ii is your answer, because wwi had already ended at 1918, and the cold war was after 1945.

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b would have to be the answer