A sentence fragment is an incomplete thought that has both subject and predicate but the connection between the two is not built. To proofread sentence fragments, we have to add an independent clause to complete a sentence and then add conjunctions to connect the two clauses.
The best way to combine both of the sentences would be: Soldiers and civilians began using the nickname Uncle Sam to refer to the United States.
The correct answer should be D. imaginative.
Analytical and simple are the opposite of this paragraph, and it's nor rambling because it makes sense. Rambling is mostly when something is rather long and a bit confusing.