There are four teenage boys--Eric, Francis, George, and Henry--each of whom has a girlfriend. One day, these four boys get together and have a nice long chat about their girlfriends. However, by the time the party is over, they all have forgotten the names of the others' girlfriends (except their own girlfriend's name). Being childish as ever, all of them refused to say their girlfriend's name again.
Then the following conversation takes place:
George: "Well, my girlfriend's name isn't Erica. Does this help?"
Henry: "How would that help? Even if my girlfriend is Erica, which I won't admit or deny, I still don't know everyone's girlfriend's name. By the way, my girlfriend's name is not Georgia."
Francis: "That's interesting. My girlfriend's name does not share the same initial as mine, either."
Eric: "So Francis's girlfriend isn't Frances. Since everyone makes the assertion that their girlfriend is not of a particular name, let me join in as well: my girlfriend's name isn't Henrietta."
George: "Well, this is going nowhere. Let me give you guys another hint: my girlfriend's name is not Georgia either."
Then unbeknownst to us, someone interjects: "Finally, I know everyone's girlfriend's name."
If everyone is perfectly logical and speaks the truth, then who is the person that interjects the final statement?
Note: Each of the names of their girlfriends was spoken in the conversation above at least once.