Question: The 2003 Auto Club 500 was won by the 2004 champion of what?

full_context: Document 1: 2004 NASCAR Busch Series: The 2004 NASCAR Busch Series season began on February 14 and ended on November 20. Martin Truex, Jr. of Chance 2 Motorsports won the championship.
Document 2: 2004 Auto Club 500: The 2004 Auto Club 500 was a NASCAR Nextel Cup Series stock car race held on May 2, 2004 at California Speedway in Fontana, California. Contested over 250 laps on the 2-mile (3.23 km) asphalt D-shaped oval, it was the tenth race of the 2004 NASCAR Nextel Cup Series season. Jeff Gordon of Hendrick Motorsports won the race.
Document 3: Rodney Childers: Rodney Childers (born June 7, 1976) is an American Monster Energy NASCAR Cup Series crew chief and former stock car racing driver. He is currently employed at Stewart-Haas Racing as the crew chief for the No. 4 Ford Fusion, driven by Kevin Harvick, winner of the 2014 NASCAR Sprint Cup Series championship. Childers was born in Mooresville, North Carolina.
Document 4: Al Unser: Alfred "Al" Unser (born May 29, 1939) is an American automobile racing driver, the younger brother of fellow racing drivers Jerry and Bobby Unser, and father of Al Unser Jr.. Now retired, he is the second of three men to have won the Indianapolis 500-Mile Race four times, the fourth of five to have won the race in consecutive years, and won the National Championship in 1970, 1983, and 1985. He is the only person to have both a sibling (Bobby) and child (Al Jr.) as fellow Indy 500 winners. Al's nephews Johnny and Robby Unser have also competed in that race.
Document 5: 2007 Auto Club 500: The 2007 Auto Club 500 was the second race in the 2007 NASCAR Nextel Cup season. It was held on February 25, 2007 at Auto Club Speedway in Fontana, California.
Document 6: 2003 Auto Club 500: The 2003 Auto Club 500 was a NASCAR Winston Cup Series stock car race held on April 27, 2003 at California Speedway in Fontana, California. Contested over 250 laps on the 2-mile (3.23 km) asphalt D-shaped oval, it was the tenth race of the 2003 NASCAR Winston Cup Series season. Steve Park of DEI won the pole. Kurt Busch of Roush Racing won the race. This was also the last race for Jerry Nadeau. His career ended with an injury during practice at Richmond
Document 7: Kurt Busch: Kurt Thomas Busch (born August 4, 1978) is an American professional stock car racing driver. He currently drives the No. 41 Ford Fusion for Stewart-Haas Racing in the Monster Energy NASCAR Cup Series. He was the 2004 NASCAR Nextel Cup Series champion. Busch is currently a free agent for 2018, but Stewart-Haas Racing expects him back. He is the older brother of 2015 NASCAR Sprint Cup Series champion Kyle Busch. The brothers are second-generation racing drivers; their father, Tom, won several NASCAR-sanctioned events.
Document 8: Auto Club 400: The Auto Club 400 is a 400-mile (643.737 km) Monster Energy NASCAR Cup Series stock car race held at the Auto Club Speedway in Fontana, California. Prior to 2005, the race was held in late April or early May, and until 2010, the race was run at a length of 500 miles. When the NASCAR Realignment of 2005 was made, the race was moved to February and the week following the Daytona 500. The February date stayed until the 2011 season when the date changed to March. After being pleased with the results of the shortening of the track's former fall race date, the Pepsi Max 400, from 500 to 400 miles Auto Club Speedway decided to do the same thing to its spring race.
Document 9: A. J. Foyt IV: Anthony Joseph "A. J." Foyt IV (born May 25, 1984) is an American race car driver and also is a scouting assistant for the Indianapolis Colts. He competed in the IndyCar Series and briefly in the NASCAR Nationwide Series, then called the Busch Series. He is the grandson of A. J. Foyt.
Document 10: 2003 Food City 500: The 2003 Food City 500 was the sixth stock car race of the 2003 NASCAR Winston Cup Series. It was held on March 23, 2003, before a crowd of 160,000, in Bristol, Tennessee, at Bristol Motor Speedway, one of five short tracks to hold NASCAR races. The 500-lap race was won by Kurt Busch of the Roush Racing team after starting from ninth position. Matt Kenseth finished in second and Bobby Labonte came in third.
Document 11: 2010 Auto Club 500: The 2010 Auto Club 500 was a NASCAR Sprint Cup Series race held on February 21, 2010 at Auto Club Speedway in Fontana, California. Contested over 250 laps, it was the second race of the 2010 Sprint Cup Series season. The race was won by Jimmie Johnson for Hendrick Motorsports. Kevin Harvick finished second and Jeff Burton clinched third.
Document 12: 2013 NRA 500: The 2013 NRA 500 was NASCAR Sprint Cup Series stock car race held on April 13, 2013, at Texas Motor Speedway in Fort Worth, Texas, United States. Contested over 334 laps on the 1.5–mile (2.4 km) quad-oval, it was the seventh race of the 2013 Sprint Cup Series championship. Kyle Busch of Joe Gibbs Racing won the race, his second win of the 2013 season and first at Texas, while Martin Truex, Jr. finished second. Carl Edwards, Greg Biffle, and Joey Logano rounded out the top five.
Document 13: Kevin Harvick: Kevin Michael Harvick (born December 8, 1975) is an American professional stock car racing driver. He currently competes full-time in the Monster Energy NASCAR Cup Series, driving the No. 4 Ford Fusion for Stewart-Haas Racing and part-time in the Xfinity Series, driving the No. 41 Ford Mustang for SHR. Harvick is the former owner of Kevin Harvick Incorporated, a race team that fielded cars in the Xfinity and Camping World Truck Series between 2004 and 2011. He is the 2014 NASCAR Sprint Cup Series champion and a two-time Xfinity Series champion. Harvick holds the all-time record for Cup Series wins at Phoenix International Raceway with eight wins. Harvick is also the third winningest driver in Xfinity Series history with 46 wins.
Document 14: 2006 Auto Club 500: The 2006 Auto Club 500 was the second race of the 2006 NASCAR Nextel Cup season. It was held on February 26, 2006 at Auto Club Speedway in Fontana, California.
Document 15: Kyle Busch: Kyle Thomas "Rowdy" Busch (born May 2, 1985) is an American professional stock car racing driver and team owner. He is the driver of the No. 18 Toyota Camry in the Monster Energy NASCAR Cup Series and the No. 18 Camry in the NASCAR Xfinity Series for Joe Gibbs Racing. He also owns Kyle Busch Motorsports, which runs multiple trucks in the Camping World Truck Series. Busch is the 2009 NASCAR Nationwide Series champion and the 2015 NASCAR Sprint Cup Series champion.
ground_truth: NASCAR Nextel Cup Series