Answer: The pronoun "it" should be changed to "the song"
Explanation: The last option is the only one which solves the ambiguity of the pronoun "it," whose antecedent in this sentence was not clearly defined and could have been "the guitar" or "the song." All the other options lead to invalid sentences: "we" is always a subject, not an object in this sentence (so it can't be changed to "us"), replacing "he" with "they" would break coherence with "<em>his</em> guitar" and the possessive pronoun "his" would lose its function if changed to the reflexive pronoun "himself".
This probably means that the choice is yours. Your the author of the script of your life because you get to write your own story and make your own choices. Your the captain of your ship for the same thing. You sail wherever you want to lead your life too/
