I believe it's B. Second person pronoun since it seems to be a secondary character referring to another character.
Answer:
A1 : He was mad that they helped the dwarves and wanted revenge.
A2: Bilbo told him
A3: He cares for other people other than his own
A4: He comes back with the Raven whom the dwarves are familiar with.
A5: They knew others were coming and would want the treasure
Explanation:
A natural and untrained musical note resembling the song of a bird
Answer:
Some people like dogs, others prefer cats.
Explanation:
You can add a comma after dogs.