Question: Between My Dog Tulip and Superman/Batman: Public Enemies, which film was directed by Sam Liu?

Context paragraphs:
My Dog Tulip: My Dog Tulip is an American independent animated feature film based on the 1956 memoir of the same name by J. R. Ackerley, BBC editor, novelist and memoirist.  The film tells the story of Ackerley's fifteen-year relationship with his Alsatian dog (German Shepherd) "Queenie", who had been renamed "Tulip" for the book.  The film – geared toward an adult audience – was adapted, directed and animated by Paul Fierlinger with backgrounds and characters painted by his wife, Sandra Fierlinger.

Batman: The Killing Joke (film): Batman: The Killing Joke is a 2016 American animated superhero film produced by Warner Bros.  Animation and distributed by Warner Bros.  Pictures.  Featuring the DC Comics character Batman, the film is the twenty-sixth film in the DC Universe Animated Original Movies series, based on the by Alan Moore and Brian Bolland.  The film is directed by Sam Liu, written by Brian Azzarello and stars the voices of Kevin Conroy, Mark Hamill, Tara Strong, and Ray Wise.  Like the novel, the film follows the Joker's undertaking to drive police commissioner James Gordon insane, and Batman's desperate attempts to stop him.

Superman/Batman: Public Enemies: Superman/Batman: Public Enemies is a 2009 original direct-to-video animated superhero film adaptation of "Public Enemies"—the opening story arc of DC Comics' "Superman/Batman"—which focuses on Superman and Batman teaming up to prevent a meteorite from striking Earth and take down Lex Luthor, who has been elected President of the United States.  The film is the sixth in the line of the DC Universe Animated Original Movies line released by Warner Premiere and Warner Bros.  Animation.  Voice actors from the DCAU reprised their roles, although it is not a DCAU production and is said not to be connected with that universe beyond sharing of voice actors.  The film is directed by Sam Liu.

Public Enemies (2009 film): Public Enemies is a 2009 American biographical mob drama film directed by Michael Mann and written by Mann, Ronan Bennett and Ann Biderman.  It is an adaptation of Bryan Burrough's non-fiction book "Public Enemies: America's Greatest Crime Wave and the Birth of the FBI, 1933–34".  Set during the Great Depression, the film chronicles the final years of the notorious bank robber John Dillinger (Johnny Depp) as he is pursued by FBI agent Melvin Purvis (Christian Bale), Dillinger's relationship with Billie Frechette (Marion Cotillard), as well as Purvis' pursuit of Dillinger's associates and fellow criminals Homer Van Meter (Stephen Dorff) and Baby Face Nelson (Stephen Graham).

Superman (serial): Superman (1948) is a 15-part black-and-white Columbia film serial based on the comic book character Superman.  It stars an uncredited Kirk Alyn (billed only by his character name, Superman; but credited on the promotional posters) and Noel Neill as Lois Lane.  Like "Batman", it is notable as the first live-action appearance of Superman on film and for the longevity of its distribution.  The serial was directed by Thomas Carr, who later directed many early episodes of the "Adventures of Superman" television show, and Spencer Gordon Bennet, produced by Sam Katzman and shot in and around Los Angeles, California.  It was originally screened at movie matinées and after the first three scene-setting chapters, every episode ends in a cliffhanger.  The Superman-in-flight scenes are animations, in part due to the small production budget.

Batman v Superman: Dawn of Justice: Batman v Superman: Dawn of Justice is a 2016 American superhero film featuring the DC Comics characters Batman and Superman.  Directed by Zack Snyder and distributed by Warner Bros.  Pictures, the film is the second installment in the DC Extended Universe (DCEU) following 2013's "Man of Steel".  It was written by Chris Terrio and David S. Goyer, and features an ensemble cast that includes Ben Affleck, Henry Cavill, Amy Adams, Jesse Eisenberg, Diane Lane, Laurence Fishburne, Jeremy Irons, Holly Hunter and Gal Gadot.  "Batman v Superman: Dawn of Justice" is the first live-action film to feature Batman and Superman together, as well as the first live-action cinematic portrayal of Wonder Woman, Aquaman, Flash and Cyborg.  In the film, criminal mastermind Lex Luthor manipulates Batman into a preemptive battle with Superman, whom Luthor is obsessed with defeating.

Superman/Batman: Apocalypse: Superman/Batman: Apocalypse is a 2010 direct-to-video animated superhero film based on the "Superman/Batman" comic storyline "The Supergirl from Krypton" and is a sequel to "".  The art style is partly based on that of Michael Turner, who penciled the "Superman/Batman" comic book arc.  The film is the ninth in the DC Universe Animated Original Movies line released by Warner Premiere and Warner Bros.  Animation and the first sequel in the line.  It was released on September 28, 2010.  The film stars Andre Braugher, Kevin Conroy, Tim Daly and Summer Glau.  Despite the title, the film focuses primarily on the introduction of Supergirl and her relationship with Superman.  Batman plays a supporting role.

Batman: Year One (film): Batman: Year One is a 2011 animated superhero film, based on the printed in 1987.  It premiered at Comic-Con on July 22 and was officially released October 18, 2011.  The film was directed by Lauren Montgomery and Sam Liu.  It is the 12th film released under the DC Universe Animated Original Movies banner, and was released on DVD, Blu-ray, and Digital copy.

Ra's al Ghul: Ra's al Ghul (Arabic: رأس الغول‎ ‎ "Raʾs al-Ġūl"; "Ghoul's Head" or "Demon's Head") is a fictional supervillain appearing in American comic books published by DC Comics, commonly as an adversary of the superhero Batman.  Created by editor Julius Schwartz, writer Dennis O'Neil and artist Neal Adams, the character first appeared in "Batman" #232's "Daughter of the Demon" (June 1971).  The character is one of Batman's most enduring enemies and belongs to the collective of adversaries that make up Batman's rogues gallery, though given his high status as a supervillain, he has also come into conflict with Superman and other superheroes in the DC Universe.

Teen Titans: The Judas Contract: Teen Titans: The Judas Contract is a 2017 direct-to-video animated superhero film directed by Sam Liu from a screenplay by Ernie Altbacker based on "The Judas Contract" by Marv Wolfman and George Pérez.  It is the twenty-eighth film in the DC Universe Animated Original Movies series and is the sequel to "Justice League vs. Teen Titans" (2016).  The film features the voices of Christina Ricci, Taissa Farmiga, Miguel Ferrer, Stuart Allan, Brandon Soo Hoo, Jake T. Austin, Kari Wahlgren, Sean Maher, Gregg Henry, and Meg Foster.  The film marks Ferrer's final role before his death from throat cancer.

Supporting paragraphs: My Dog Tulip Superman/Batman: Public Enemies
Answer: Superman/Batman: Public Enemies