Who was the Pharaoh of the Exodus?

New Evidence is presented that 13th dynasty Pharaoh Merneferre Ay is the pharaoh of the exodus; the pharaoh to whom Moses said, "Thus says the Lord: 'Let my people go!'" (Ex 5.1)

Evidence for this new theory by Duane Caldwell is in the Rational Faith Article:

Do Ancient Chronologies Challenge the Bible?
Part 2: Egyptian Chronology & the Pharaoh of the Exodus