"One of these sentences contains error in Fragments, Comma Faults, Fused Sentences (errors that result when part of a sentence is punctuated as a complete sentence or two complete sentences are incorrectly joined)

A. After World War II, Nazism was no longer a threat, then Communism became our foe.
B. Before the Renaissance, religious themes dominated Italian painting; secular ones crept in and then prevailed in ensuing years.
C. The best way to evade an alligator on the attack, experts say, is to zigzag as you run.
D. Most primitive cultures have highly developed taboo systems that divide the sacred from the profane.
I think the answer is B.

No. Please study comma faults again.

I think the answer is A, just add but b/w threat and Communism.

Yes, A has a common error. Instead of the comma a semi-colon is needed to connect two complete sentences.

Thank you both so much!!

You are entirely welcome!

To determine which sentence contains an error in fragments, comma faults, or fused sentences, you will need to examine each sentence closely.

A. After World War II, Nazism was no longer a threat, then Communism became our foe.
This sentence is correct. It does not contain any errors in fragments, comma faults, or fused sentences. It is a compound sentence with two independent clauses joined by the coordinating conjunction "then."

B. Before the Renaissance, religious themes dominated Italian painting; secular ones crept in and then prevailed in ensuing years.
This sentence is correct as well. It is a compound sentence with two independent clauses joined by the coordinating conjunctions "and" and "then." It does not contain any errors.

C. The best way to evade an alligator on the attack, experts say, is to zigzag as you run.
This sentence is also error-free. It is a complete sentence and does not have any fragments, comma faults, or fused sentences.

D. Most primitive cultures have highly developed taboo systems that divide the sacred from the profane.
This sentence is correct. It is a complete sentence and does not contain any errors.

Based on the analysis, the correct answer is that none of the given sentences contain errors in fragments, comma faults, or fused sentences. Therefore, the answer is not B.