Question: Who hosted the show NASCAR on the network that aired the show that had an episode called Known Unknowns?

full_context: Document 1: American Idol: Season eleven, however, suffered a steep drop in ratings, a drop attributed by some to the arrival of new shows such as The Voice and The X-Factor. The ratings for the first two episodes of season eleven fell 16–21% in overall viewer numbers and 24–27% in the 18/49 demo, while the season finale fell 27% in total viewer number and 30% in the 18-49 demo. The average viewership for the season fell below 20 million viewers the first time since 2003, a drop of 23% in total viewers and 30% in the 18/49 demo. For the first time in eight years, American Idol lost the leading position in both the total viewers number and the 18/49 demo, coming in second to NBC Sunday Night Football, although the strengths of Idol in its second year in the Wednesday-Thursday primetime slots helped Fox achieve the longest period of 18-49 demographic victory in the Nielsen ratings, standing at 8 straight years from 2004 to 2012.
Document 2: Greg Biffle: Gregory Jack Biffle (born December 23, 1969) is an American professional stock car racing driver. He is inactive as of 2017, last driving in the No. 16 Ford Fusion for Roush Fenway Racing. After racing in the NASCAR Winter Heat Series in the mid-1990s, he was recommended to Jack Roush by former announcer Benny Parsons. He was the 1998 NASCAR Craftsman Truck Series Rookie of the Year. He won the 2000 Craftsman Truck championship. He reprised this progression in the NASCAR Busch Series, winning the 2001 Rookie of the Year, immediately followed by winning the 2002 championship. Biffle drove in the NASCAR Sprint Cup Series for Roush from 2003 until 2016, winning 19 races in the No. 16 Ford. He currently is an analyst for NBC Sports' show NASCAR America.
Document 3: American Idol: American Idol premiered in June 2002 and became the surprise summer hit show of 2002. The first show drew 9.9 million viewers, giving Fox the best viewing figure for the 8.30 pm spot in over a year. The audience steadily grew, and by finale night, the audience had averaged 23 million, with more than 40 million watching some part of that show. That episode was placed third amongst all age groups, but more importantly it led in the 18–49 demographic, the age group most valued by advertisers.
Document 4: Abby Lockhart: At the end of the thirteenth season, Abby and Luka plan to honeymoon in Hawaii. However, the night before they are due to depart, Luka receives a phone call from Croatia informing him that his father is ill, so the honeymoon is put on hold until Luka can return from his urgent trip abroad. After Luka's departure, Abby has a tough time with the stern new ER Chief Kevin Moretti, who plans to mold the department into a more efficient and professional work environment, but Moretti quickly tells Abby he is very impressed with her work. Despite this, she seems to dislike him more than many of the other residents. In season 14, Abby is struggling to deal with Luka's absence, raise Joe and work at the ER; in ``Gravity '', Joe is injured after falling off a jungle gym at the playground and Abby ends up falling back into drinking at the episode's end. She approaches Dr. Janet Coburn (the O.B. Chief) who appears to have been her AA sponsor in the past. Abby's drinking problem continues to escalate, and she realizes how bad it is in`` Blackout'' when she shows up drunk to a party in honor of Pratt and Morris passing their boards. Abby finds herself waking up at 3am in Moretti's apartment realizing, after sobering up at the airport when trying to find a flight to Croatia to see Luka, that she slept with him.
Document 5: American Idol: In season ten, the total viewer numbers for the first week of shows fell 12–13%, and by up to 23% in the 18–49 demo compared to season nine. Later episodes, however, retained viewers better, and the season ended on a high with a significant increase in viewership for the finale – up 12% for the adults 18–49 demo and a 21% increase in total viewers from the season nine finale. While the overall viewer number has increased this season, its viewer demographics have continued to age year on year – the median age this season was 47.2 compared to a median age of 32.1 in its first season. By the time of the 2010–11 television season, Fox was in its seventh consecutive season of victory overall in the 18–49 demographic ratings in the United States.
Document 6: Known Unknowns: "Known Unknowns" is the seventh episode of the sixth season of "House" and 117th overall. It aired on November 9, 2009. The team tries to diagnose a teenage girl while House is away at a medical conference with Wilson and Cuddy. At the conference House finds something out about Cuddy.
Document 7: NASCAR Trackside: NASCAR Trackside was a NASCAR race themed show hosted by Krista Voda on Speed Channel. The show also featured former NASCAR driver Kyle Petty and SPEED personalities Rutledge Wood and Kaitlyn Vincie. Elliott Sadler and former NASCAR crew chief Jeff Hammond occasionally occupied the seat in Petty's absence. During the Michigan broadcast on August 13, 2010 Steve Byrnes announced he was leaving the show to be the host for "NASCAR Race Hub" also broadcast on Speed. In 2011, he hosted the show during the NASCAR on FOX Sprint Cup coverage.
Document 8: List of House episodes: "House", also known as "House, M.D.", is an American medical drama series which premiered on Fox on November 16, 2004. "House" was created by David Shore. The show follows Dr. Gregory House (Hugh Laurie), an irascible, maverick medical genius who heads a team of diagnosticians at the fictional Princeton-Plainsboro Teaching Hospital (PPTH) in New Jersey. In a typical episode, the team is presented with an unusual case; the storyline follows the diagnosis of the patient's illness, a process often complicated by the internal competition and personal foibles of the diagnostic team. The team leader, House, frequently clashes with his boss (Dr. Lisa Cuddy (Lisa Edelstein) in seasons 1 through 7, and Dr. Eric Foreman in season 8), and his only friend, Dr. James Wilson (Robert Sean Leonard).
Document 9: Tony Stewart: On September 27, 2015, Bob Pockrass reported that Stewart announced plans to retire from racing at the conclusion of the 2016 season. Stewart formally made an announcement on September 30 confirming this and announcing that Clint Bowyer would replace him in the No. 14 in 2017.
Document 10: Knight Fall: "Knight Fall" is the eighteenth episode of the sixth season of the American medical drama "House" and it is the 127th episode overall. It aired on April 19, 2010 and was directed by Juan J. Campanella.
Document 11: Deb Carson: Deb Carson is an award-winning American radio and television personality and national sports anchor for Fox Sports Radio. She currently anchors the network's National Sports Reports weekdays during "The Dan Patrick Show", "The Rich Eisen Show", and "The Herd with Colin Cowherd" . She was previously Co-Host of FSR's nationally syndicated morning drive show, "The Stephen A. Smith Show." Carson has been a frequent sports contributor to a variety of media outlets, including KFI's "The Bill Handel Show" and Premiere Networks' “America Now with Meghan McCain” and “America Now with Andy Dean,” for which she was named Outstanding Reporter/Correspondent at the 2012 Gracie Awards.
Document 12: American Idol: The enormous success of the show and the revenue it generated was transformative for Fox Broadcasting Company. American Idol and fellow competing shows Survivor and Who Wants to Be a Millionaire were altogether credited for expanding reality television programming in the United States in the 1990s and 2000s, and Idol became the most watched non-scripted primetime television series for almost a decade, from 2003 to 2012, breaking records on U.S. television (dominated by drama shows and sitcoms in the preceding decades).
Document 13: Thoroughbred Racing on NBC: Thoroughbred Racing on NBC is the "de facto" title for a series of horse races events whose broadcasts are produced by NBC Sports, the sports division of the NBC television network in the United States. Race coverage is currently helmed by, among others, host Mike Tirico, along with analysts Randy Moss and Jerry Bailey, handicappers Eddie Olczyk and Britney Eurton, reporters Kenny Rice, Donna Barton Brothers, Laffit Pincay, III and Carolyn Manno and track announcer Larry Collmus.
Document 14: 97 Seconds: "97 Seconds" is the third episode of the fourth season of "House" and the seventy-third episode overall. It aired on October 9, 2007.
Document 15: American Idol: The show pushed Fox to become the number one U.S. TV network amongst adults 18–49, the key demographic coveted by advertisers, for an unprecedented eight consecutive years by 2012. Its success also helped lift the ratings of other shows that were scheduled around it such as House and Bones, and Idol, for years, had become Fox's strongest platform primetime television program for promoting eventual hit shows of the 2010s (of the same network) such as Glee and New Girl. The show, its creator Simon Fuller claimed, "saved Fox".
ground_truth: Krista Voda
sub_queries: Of what series is Known Unknowns a part of? Answer: House
What television network originally aired the show House ? Answer: Fox
NASCAR on Fox >> cast member Answer: Krista Voda