Question: "Fat Man and Little Boy" is the fifth episode of which sixteenth season that began on Sunday, November 7, 2004 and contained 21 episodes, beginning with Treehouse of Horror XV? 

Context articles: List of The Simpsons Treehouse of Horror episodes
Fat Man and Little Boy (The Simpsons)
Treehouse of Horror XV
All That (season 5)
All That (season 3)
Treehouse of Horror XXI
The Simpsons (season 16)
Fat Man and Little Boy
Nashville (season 4)
Fat Man

This is a list of "Treehouse of Horror" episodes produced by the animated television series "The Simpsons".
 "Treehouse of Horror" episodes have aired annually since the second season (1990) and each episode has three separate segments.
 These segments usually involve the family in some horror, science fiction, or supernatural setting and always take place outside the normal continuity of the show and are therefore considered to be non-canon. "
Treehouse of Horror" episode aired on October 25, 1990 and was inspired by EC Comics Horror tales.
 Before "Treehouse of Horror XI", which aired in 2000, every episode has aired in the week preceding or on October 31; "Treehouse of Horror II" and "Treehouse of Horror X" are the only episodes to air on Halloween.
 Between 2000 and 2011, due to Fox's contract with Major League Baseball's World Series, several episodes have originally aired in November; as of 2011 every "Treehouse of Horror" episode has aired during the month of October.
 From "Treehouse of Horror" to "Treehouse of Horror XIII", all three segments were written by different writers and in some cases there was a fourth writer that wrote the opening and wraparound segments.
 For "Treehouse of Horror", there were even three different directors for the episode.
 Starting with season fifteen's "Treehouse of Horror XIV", only one writer was credited as having written a "Treehouse of Horror" episode, and the trend has continued since.
"Fat Man and Little Boy" is the fifth episode of the 16th season of "The Simpsons".
 It originally aired on the Fox network in the United States on December 12, 2004.
"Treehouse of Horror XV" is the first episode of the sixteenth season of "The Simpsons".
 It originally aired on the Fox network in the United States on November 7, 2004.
 In the fifteenth annual "Treehouse of Horror", Ned Flanders' head injury gives him the power to predict others' deaths, Bart and Lisa play detective when a string of Victorian-era prostitutes are murdered by Jack the Ripper, and the Simpsons go on a fantastic voyage inside Mr. Burns' body to save Maggie.
 It was written by Bill Odenkirk and directed by David Silverman.
 Around 11.29 million Americans tuned in to watch the episode during its original broadcast.
"All Thats fifth season"' ran from December 12, 1998 to May 22, 1999.
 The season contained 21 episodes with a 100th Episode Special Midway.
"All Thats third season"' ran from November 16, 1996 to October 18, 1997.
 This season of "All That" contained 21 episodes.
"Treehouse of Horror XXI" is the fourth episode of "The Simpsons"<nowiki>'</nowiki> twenty-second season.
 It first aired on the Fox network in the United States on November 7, 2010.
 This is the 21st "Treehouse of Horror" episode, and, like the other "Treehouse of Horror" episodes, consisted of three self-contained segments: In "War and Pieces", Bart and Milhouse discover a real-life board game that they must win to return home; in "Master and Cadaver", Marge and Homer go on a honeymoon on a sailboat, and rescue a mysterious castaway named Roger; and in "Tweenlight", Lisa falls in love with a vampire named Edmund.
"The Simpsons"' sixteenth season (November 7, 2004 - May 15, 2005) began on Sunday, November 7, 2004 and contained 21 episodes, beginning with Treehouse of Horror XV.
 The season contains six hold-over episodes from the season 15 (FABF) production line.
 Season 16 was released in Region 1 on December 3, 2013, Region 2 on December 2, 2013, Region 4 on December 11, 2013.
Fat Man and Little Boy (a.k.a. Shadow Makers in the UK) is a 1989 film that reenacts the Manhattan Project, the secret Allied endeavor to develop the first nuclear weapons during World War II.
 The film is named after the weapons "Little Boy" and "Fat Man" that were detonated over Hiroshima and Nagasaki, respectively.
 The code names, originally Fat Man and Thin Man, were drawn from characters in the works of Dashiell Hammett.
 However, there's a possible secondary allusion to stout project director Gen. Leslie Groves and the slim scientific director, Dr. J. Robert Oppenheimer.
 The film focuses much attention on the frequently strained relationship between the two men.
The fourth season of the American television drama series "Nashville", created by Callie Khouri, premiered on September 23, 2015, on ABC and concluded on May 25, 2016.
 The show features an ensemble cast with Connie Britton and Hayden Panettiere in the leading roles as two country music superstars, Rayna Jaymes and Juliette Barnes.
 The season contained 21 episodes.
"Fat Man" was the codename for the atomic bomb that was detonated over the Japanese city of Nagasaki by the United States on 9 August 1945.
 It was the second of the only two nuclear weapons ever used in warfare, the first being Little Boy, and its detonation marked the third-ever man-made nuclear explosion in history.
 It was built by scientists and engineers at Los Alamos Laboratory using plutonium from the Hanford Site and dropped from the Boeing B-29 Superfortress "Bockscar".
 For the Fat Man mission, "Bockscar" was piloted by Major Charles W. Sweeney.