I'm having some trouble with this question... Can anyone please help???

Which Greek philosopher explained that water is the essence of all matter, and how do we know about his teachings? (1 point)

Themistocles; He wrote many books about his teachings.
Thales; We know about his teachings from the writings of Herodotus.
Solon; We know about his teachings from the library at Alexandria.
Plato; Homer wrote about his teachings in the Iliad.