Coming off their road win over the Lions, the Giants went home for a Week 12 intraconference duel with the Minnesota Vikings. In the first quarter, New York trailed early as Vikings QB Tarvaris Jackson completed a 60-yard TD pass to WR Sidney Rice. The Giants responded with RB Reuben Droughns getting a 1-yard TD run. Minnesota retook the lead with safety Darren Sharper returning an interception 20 yards for a touchdown.  In the second quarter, Vikings' RB Chester Taylor got an 8-yard TD run, along with kicker Ryan Longwell making a 46-yard field goal. In the third quarter, Giants' kicker Lawrence Tynes made a 48-yard field goal, and Minnesota's Longwell made a 26-yard field goal.  In the fourth quarter, the Vikings' safety Dwight Smith returned an interception 93 yards for a touchdown, along with LB Chad Greenway returning an interception 37 yards for a touchdown.  New York's QB Eli Manning completed a 6-yard TD pass to WR Plaxico Burress to complete the scoring. Eli Manning was intercepted four times (with three of his interceptions being returned for touchdowns).  He became the third NFL QB since 1970 to have three interceptions get returned for touchdowns.  His performance was all the more embarrassing as the Vikings had the league's worst pass defense in 2007 (albeit with the league's strongest run defense), and were playing in this game without starting corner Antoine Winfield.
Question: How many defensive touchdowns did the Vikings have in the fourth quarter?
Answer: 2