Trying to snap a three-game losing streak, the Chargers stayed at home, donned their alternate uniforms again, and played a Week 14 AFC West rematch with the Oakland Raiders.  In the first quarter, the 'Bolts struck first as kicker Nate Kaeding got a 20-yard field goal, along with RB LaDainian Tomlinson getting a 3-yard TD run.  In the second quarter, San Diego increased their lead as QB Philip Rivers completed an 8-yard TD pass to RB Darren Sproles and a 59-yard TD pass to WR Vincent Jackson, while Kaeding made a 39-yard field goal.  Oakland would close out the half with CB Justin Miller returning a kickoff 98 yards for a touchdown.  After a scoreless third quarter, the 'Bolts pulled away in the fourth quarter as Rivers hooked up with Sproles again on an 18-yard TD pass.
Question: How many touchdowns were scored in the first half?
Answer: 4