Who is the first to recognize Odysseus through his disguise? Eumaeus Argos the swineherd the goatherd Telemachus Penelope

The answer is Argos.

Despite the Odysseus disguise as an old man when he gets home to Ithaca after ten years of struggle he was immediately recognize by his loyal and faithful dog. When Odysseus approaches his home, Argos was lying on a pile of cow manure and recognizes him at once as he stands and wags his tail.