Hey student! =)
Great question!
The sentence the writer is considering adding is...
At the time, Florence was a republic under the powerful influence of the Medici family.
And...
The topic of the reading passage is exactly what you mentioned: the features and history of Mona Lisa.
Tip: Be aware of sentences that are LOOSELY related (BARELY relevant). You want to choose "YES" if the sentence is DIRECTLY related to the main idea of the paragraph.
Although the sentence in the question is related to Florence, which is mentioned in the last sentence in the passage's paragraph, it is BARELY related to the topic of the paragraph, which uses Florence as a minor detail to tell the reader where the painter of the Mona Lisa lived. Aside from that one minor point, the paragraph doesn't focus on Florence at all. Plus, the sentence indicates who controlled Florence and that it was a Republic. These topics are NOT related to the paragraph's focus on Mona Lisa. So you definitley do not want to add this sentence to the paragraph.
These questions are designed to trick students who don't read carefully and who only consider matching topics on a very basic level. Don't be tricked by these types of questions.
If you are unsure whether to keep or delete the sentence, evaluate the answer choices. The sentence does not provide details that is important and relevant to Mona Lisa since the sentence just discusses the political aspects of Florence.
Practicing more of these questions can help you get better at recognizing LOOSELY related topics. =)
You got this!