Which of the following contains a correct, standard use of a comma

To determine which of the following options contains a correct, standard use of a comma, we need to review the rules of comma usage.

1. Commas are used to separate items in a list or a series. For example: "I need to buy apples, bananas, and oranges."
2. Commas are used to separate independent clauses in a compound sentence. For example: "She studied for the test, but she didn't do well."
3. Commas are used to set off introductory words, phrases, or clauses. For example: "However, I still managed to finish the project."
4. Commas are used to set off nonessential elements in a sentence. For example: "John, who is my neighbor, is a doctor."
5. Commas are used to separate two or more adjectives that modify the same noun. For example: "She wore a soft, blue scarf."

Now, let's examine the options provided and determine which one adheres to these comma usage rules.