Read the excerpt from The Riddle of the Rosetta Stone. To confirm this hunch, Champollion turned to the writings on the Rosetta Stone. There the unknown sign occurred, again in combination with p, as part of a group of hieroglyphs that correspond to the word "birthday" in the Greek passage. This made Champollion think at once of the Coptic word for "give birth," which was pronounced mes. He put that sound in place of the question mark, and there the name was: Ramesses, "The Child of Ra."

Which line in the excerpt shows what Champollion discovered?