Which type of punctuation sets off non-essential information in a sentence?

Commas are used to set off non-essential information in a sentence because they create a natural pause that signals to the reader that the information contained within the commas is additional but not crucial for understanding the main point of the sentence. This allows the reader to understand the primary idea without needing that extra information, which can be removed without altering the fundamental meaning of the sentence.

For example, in the sentence "My brother, who lives in New York, is visiting for the weekend," the phrase "who lives in New York" is non-essential. It gives extra detail about "my brother" but is not necessary to understand the main point that he is visiting. The commas effectively indicate this separation.

Other punctuation marks listed have different functions. Periods are used to end sentences, semicolons link closely related independent clauses, and colons often introduce lists or explanations. Therefore, the unique role of commas in isolating non-essential information makes them the correct answer to the question.