Question: Who is the father when Blair gets pregnant in season five of the series that had an episode called The Lost Boy?

full_context: Document 1: Gaslit: "Gaslit" is the 75th episode of the CW television series, "Gossip Girl", as well as the tenth episode of the show's fourth season. The episode was written by Robert Hull and Joshua Safran and directed by Tate Donovan. It aired on Monday, November 29, 2010 on the CW.
Document 2: The Ex Files: "The Ex Files" is the 22nd episode of the CW television series, "Gossip Girl". It was also the fourth episode of the show's second season. The episode was written by Robby Hull and directed by Jim McKay. It originally aired on Monday, September 22, 2008 on the CW.
Document 3: Blair Waldorf: In 2007, Gossip Girl was adapted for television. According to Cecily von Ziegesar, the television character is largely faithful to the original. Among the aspects to be maintained are her admiration for Audrey Hepburn and her interest in Yale University. However, the series is also noted for its deviations from the source material, including the exclusion of Blair's brother Tyler. The show also explores romances between Blair and multiple male leads, resulting in occasional love triangles. In the fifth season, Blair is revealed to be pregnant with Prince of Monaco, Louis Grimaldi's child. However the child later dies before birth after a car crash Blair and Chuck were in.
Document 4: New York, I Love You XOXO: With the death of Bart Bass, Nate Archibald (Chace Crawford) who is running the newspaper The Spectator, is no longer indebted to him (Bart paid his debts to control him) and he decides to find out for good who Gossip Girl is. Jack and Georgina Sparks (Michelle Trachtenberg) deal with the arrangements of Chuck and Blair's wedding. Before the ceremony, Serena and Blair have a conversation over why she is still talking to Dan after he published a negative chapter about her a few weeks ago. Overhearing their conversation, Dan leaves and gives to Nate his final chapter, which is about Gossip Girl. Blair and Chuck are married by Cyrus (Wallace Shawn) and right after, the police arrive to question them. At the same time, everyone's phones ring: Dan's chapter has been published in The Spectator, in which he reveals that he is Gossip Girl. Various characters react over the Gossip Girl reveal, including Vanessa (Jessica Szohr), Juliet (Katie Cassidy), Agnes (Willa Holland) and Lola (Ella Rae Peck), as well as Mayor Michael Bloomberg. Rachel Bilson, preparing to audition for a role in the adaptation of Dan's book, is told of Gossip Girl's identity by Kristen Bell, who shares a conspiratorial wink with the audience. Dan finally explains why he created Gossip Girl and says Jenny (Taylor Momsen) knew it all along.
Document 5: Chuck Bass: Chuck Bass Gossip Girl character Ed Westwick as Charles Bass First appearance Novel: Gossip Girl Television: ``Pilot ''(episode 1.01) Last appearance Novel: I Will Always Love You Television:`` New York, I Love You XOXO'' (episode 6.10) Created by Character Cecily von Ziegesar Developed for Television Josh Schwartz Stephanie Savage Portrayed by Ed Westwick Information Full name Charles Bartholomew Bass Nickname (s) Chuck (by everyone except Lily) Aliases Television: Henry Prince Occupation Television: Entrepreneur High school student (at St. Jude's; graduated) Title Television: CEO of Bass Industries Family Television: Bartholomew ``Bart ''Bass (father; deceased) Elizabeth Fisher (mother; alias: Evelyn Bass) Lillian`` Lily'' van der Woodsen (adoptive mother; née Rhodes) Serena van der Woodsen (adoptive sister) Eric van der Woodsen (adoptive brother) Spouse (s) Television: Blair Waldorf (wife) Children Television: Henry Bass (with Blair; flash - forward)
Document 6: Blair Waldorf: Blair Cornelia Waldorf is the lead character of "Gossip Girl", introduced in the original series of novels and also appearing in the television and comic adaptations. Described as "a girl of extremes" by creator Cecily von Ziegesar, she is a New York City socialite and a comical overachiever who possesses both snobbish and sensitive sides. Due to her position as queen bee of Manhattan's social scene, Blair's actions and relations are under constant scrutiny from the mysterious Gossip Girl, a popular blogger.
Document 7: The Hurt Locket: "The Hurt Locket" is the 56th episode of the CW television series, "Gossip Girl". It was also the thirteen episode of the show's third season. The episode was written by Sara Goodman and directed by Tony Wharmby. It originally aired on Monday, March 8, 2010 on the CW.
Document 8: The Lost Boy (Gossip Girl): "The Lost Boy" is the 46th episode of the CW television series, "Gossip Girl". It was also the third episode of the show's third season. The episode was written by Robert Hull and directed by Jean de Segonzac. It originally aired on Monday, September 28, 2009 on the CW.
Document 9: Gossip Girl (season 3): As the summer is drawing to a close, Blair and Chuck are madly in love and adjusting to their new ``in a relationship ''status, breaking all traditional rules of dating as would be expected. Meanwhile, Serena returns from her European adventure with many secrets to hide and a complicated relationship with Carter Baizen. Nate returns from his travels with a mysterious brunette, Bree Buckley (guest star Joanna Garcia) in town. With Lily away in California visiting her mother, Rufus, Dan, and Jenny spent the summer in the Hamptons, adjusting to the van der Woodsen's glamorous lifestyle surprisingly faster than any of them expected. Vanessa introduces her new boyfriend, Scott, to Dan and Rufus.
Document 10: The Debarted (Gossip Girl): "The Debarted" is the 55th episode of the CW television series, "Gossip Girl". It was also the twelfth episode of the show's third season. The episode was written by executive producer and one of the series' creator Stephanie Savage and directed by Jason Ensler. It originally aired on Monday, December 7, 2009 on the CW.
Document 11: List of Gossip Girl characters: Portrayed by John Shea in seasons one, two and five. Harold Waldorf is Blair's father who went to France to live with his male lover Roman. He traditionally makes pumpkin pie during Thanksgiving but has n't made it since Blair's last Thanksgiving with him, before he came out and left for Europe. He returns for the holidays with his partner, Roman, a model once used by Harold's ex-wife, Eleanor. Roman earns Blair's spite during Christmas by breaking his leg, inviting an old flame of Roman's that frustrates Harold. Harold speaks with Blair about the incident and then shows her his life in France through a video. He now lives in France, tending a vineyard and has a cat named Cat, the same name as the cat in Blair's favorite movie, Breakfast at Tiffany's. He returns in the second season during Thanksgiving when Blair first thought that her mother did n't invite him. He and Blair share a pie during thanksgiving. He gives Blair a bulldog named Handsome Dan whom Blair renames Handsome. During Blair's hazing incident that sparked a controversy with Miss Carr and Dan and the almost removal of Gossip Girl's blog, Blair convinces her father and the parent's council of Constance - St. Jude's by showing a picture of Dan in a compromising position with Miss Carr, thus securing her admission to Yale. When he overhears Blair's conversation about the picture only being eerily prophetic and untrue, Harold speaks with Blair and tells her that he saw a different side of her and is disappointed that he lied for her indirectly. He then tells Blair that the college she is admitted to does n't matter and that the person she becomes matters more.
Document 12: They Shoot Humphreys, Don't They?: "They Shoot Humphreys, Don't They?" is the 52nd episode of the CW television series, "Gossip Girl". It was also the ninth episode of the show’s third season. The episode was written by Amanda Lasher and directed by Alison MacLean. The episode was considered very polemic according to the Parents Television Council. It originally aired on Monday, November 9, 2009 on the CW.
Document 13: List of Gossip Girl characters: The following is a list of characters for The CW teen television drama series, Gossip Girl. The show is based on the popular book series of the same name, written by author Cecily von Ziegesar. The series features nine regular characters and follows the storylines of several high school students, who attend the fictional preparatory school, ``Constance Saint Jude '': Blair Waldorf (Leighton Meester), the`` Queen Bee'' at Constance, who is notorious for her ``minions ''and scheming; her best friend and The 'It - Girl' of the Upper East Side, Serena van der Woodsen (Blake Lively); Serena's new love interest, and so - called`` lonely boy'' Dan Humphrey (Penn Badgley); Blair's boyfriend, the 'golden boy,' better known as Nate Archibald (Chace Crawford); Dan's little sister, a 14 - year - old freshman at Constance, Jenny Humphrey (Taylor Momsen); Nate's best friend, the wealthy playboy Chuck Bass (Ed Westwick); Dan's best friend and ex-lover, the creative Vanessa Abrams (Jessica Szohr); Serena's mother, a socialite and philanthropist and frequent divorcée, Lily van der Woodsen (Kelly Rutherford), and also Dan Humphrey's father, former rock star turned art gallery owner, Rufus Humphrey (Matthew Settle). The story unfolds in the Upper East Side of Manhattan as well as Brooklyn, in New York. Momsen and Szohr left the series in season five, while Kaylee DeFer was added to the main cast, portraying Ivy Dickens, a con artist who pretends to be Serena's maternal cousin, Charlie Rhodes. The series is narrated by a seemingly omniscient character, ``Gossip Girl ''(voiced by Kristen Bell).
Document 14: The Townie: "The Townie" is the 76th episode of the CW television series, "Gossip Girl", as well as the eleventh episode of the show's fourth season. The episode was written by Amanda Lasher and Stephanie Savage and directed by Joe Lazarov. It aired on Monday, December 6, 2010 on the CW.
Document 15: Gossip Girl (season 5): While working as a production assistant in Hollywood, Serena makes a mistake while trying to impress her new boss (guest star Michael Michele). Chuck and Nate arrive in Los Angeles to visit Serena where Nate gets involved with a shady older woman (guest star Elizabeth Hurley) and Chuck has a meeting of minds with actress / stuntwoman Zoë Bell (playing herself) as he struggles to get over Blair. Meanwhile, Blair and Louis return to New York from Monaco after spending the summer planning their wedding. Louis' problem in supporting Blair's difficult choices and nearly impossible demands threatens their relationship when she begins to see him as weak. Also, Dan gets help from Louis in a desperate attempt to prevent his book from being published in a local magazine. It is revealed in this episode that Dorota is pregnant and expecting her second child. Towards the end of the episode, it is also hinted that Blair is the one that is pregnant in which Dorota lied for her. As she is fitted for her wedding dress, the dress fitter says that by the time of her wedding she will be showing. Also, Serena runs into Charlie in Los Angeles still unaware of her real identity: Ivy Dickens, who has moved to California with her boyfriend, Max.
ground_truth: Louis Grimaldi
sub_queries: The Lost Boy >> part of the series Answer: Gossip Girl
Gossip Girl season 5 blair pregnant who's the father Answer: Louis Grimaldi