The answer is "Antinous is responding to Telemachus's speech."
Because you know he isn't talking about himself. Odysseus was the King of Ithaca, and that would make it Telemachus's by birth. And Athen barely spoke to Telemachus, she mostly dealt with Odysseus. And you know it can't be Telemachus talking to Antinous, because he would only have a right to the throne if he married Penelope, plus he was super arrogant and would probably be told at some point that he was rude.
