The Chiefs began their season at home for a division rivalry match against the San Diego Chargers. In the first quarter the Chiefs trailed early as QB Philip Rivers completed a 3-yard TD pass to TE Antonio Gates. The Chiefs replied when RB Jamaal Charles made a 56-yard TD run. In the 2nd quarter the Chiefs took the lead with QB Matt Cassel completing a 2-yard TD pass to TE Tony Moeaki. This was followed by WR Dexter McCluster returning a punt 94 yards to the endzone for a touchdown. In the third quarter the Chargers cut the lead when QB Philip Rivers threw a 59-yard TD pass to WR Legedu Naanee. In the 4th quarter the Chiefs defense prevented any more scoring giving themselves a win.
Question: who is the Chiefs' quarterback?
Answer: Matt Cassel