The answer is C: slaying the gorgon and sea serpent.
Perseus, the son of Danaë and Zeus, is famous for his bravery and fighting skills which he demonstrated in several mythological passages, but two events stand out: the slaying of Medusa (who could turn men into stone), the only one of the Gorgon sisters that was mortal, and the slaying of the sea serpent that was terrorizing the people of Aethiopia, and saving, in the way, the life of the beautiful Andromeda who he would later marry.
