B. You can be used as both. Here is an example. "You said you wanted this bear, so I got it for you." You is used as both a subject and object pronoun.
Extra words in a sentence that add detail and are set off by commas are called nonessential elements. This is because they are not essential to the sentence and story, they are simply an added bonus, without them the sentence still makes sense.
I do, i think its a decent song, but its not in my top 20.
