Answer:
The setting of the book is Gordon High School in Spring 1969. The plot revolves around a history teacher Mr. Ben Ross, his high school students, and an experiment he conducts in an attempt to teach them what it may have been like living in Third Reich Germany.
B. Though Benjamin Franklin was known for his instrumental role in the founding of the United States.
This is a sentence fragment, you can tell because saying the sentence in your head or out loud feels incomplete, that is because the sentence wasn't finished, for example, "Though Benjamin Franklin was known for his instrumental role in the founding of the United States, he had many other accomplishments." Is a full sentence.