question: In the novels about Harry Potter and his friends Hermione Granger and Ron Weasley, which movie has the first appearance of the main protagonist?
answer: "Harry Potter and the Philosopher's Stone"
context: Title: Dumbledore's Army
  Passage: Dumbledore's Army (or D.A. for short) is a fictional student organisation in J. K. Rowling's "Harry Potter" series that is founded by the main characters, Harry Potter, Ron Weasley and Hermione Granger, to stand up against the regime of Hogwarts High Inquisitor Dolores Umbridge, as well as to learn practical Defence Against the Dark Arts.  It was founded in the fifth book, "Harry Potter and the Order of the Phoenix".  Cho Chang conceives of the abbreviation "D.A." and Ginny Weasley conceives of the name "Dumbledore's Army".
  Title: Harry Potter
  Passage: Harry Potter is a series of fantasy novels written by British author J. K. Rowling.  The novels chronicle the life of a young wizard, Harry Potter, and his friends Hermione Granger and Ron Weasley, all of whom are students at Hogwarts School of Witchcraft and Wizardry.  The main story arc concerns Harry's struggle against Lord Voldemort, a dark wizard who intends to become immortal, overthrow the wizard governing body known as the Ministry of Magic, and subjugate all wizards and muggles, a reference term that means non-magical people.
  Title: Harry Potter and the Philosopher's Stone (film)
  Passage: Harry Potter and the Philosopher's Stone (released in some countries as Harry Potter and the Sorcerer's Stone) is a 2001 British-American fantasy film directed by Chris Columbus and distributed by Warner Bros.  Pictures.  It is based on the novel of the same name by J. K. Rowling.  The film is the first instalment in the long-running "Harry Potter" film series, and was written by Steve Kloves and produced by David Heyman.  Its story follows Harry Potter's first year at Hogwarts School of Witchcraft and Wizardry as he discovers that he is a famous wizard and begins his education.  The film stars Daniel Radcliffe as Harry Potter, with Rupert Grint as Ron Weasley, and Emma Watson as Hermione Granger.
  Title: Rupert Grint
  Passage: Rupert Alexander Lloyd Grint (born 24 August 1988) is an English actor and producer.  He rose to prominence playing Ron Weasley, one of the three main characters in the "Harry Potter" film series.  Grint was cast as Ron at the age of 11, having previously acted only in school plays and at his local theatre group.  From 2001 to 2011, he starred in all eight "Harry Potter" films alongside Daniel Radcliffe playing as Harry Potter and Emma Watson playing as Hermione Granger.
  Title: Ron Weasley
  Passage: Ronald Bilius "Ron" Weasley is a fictional character in J. K. Rowling's "Harry Potter" series.  His first appearance was in the first book of the series, "Harry Potter and the Philosopher's Stone" as the best friend of Harry Potter and Hermione Granger.  He is a member of the Weasley family, a pure blood family, who reside in "The Burrow" outside Ottery St. Catchpole.  Along with Harry and Hermione, he is a member of the Gryffindor house.  Ron is present in most of the action throughout the series.
  Title: Lord Voldemort
  Passage: Lord Voldemort ( , or in the films; born Tom Marvolo Riddle) is a fictional character and the main antagonist in J. K. Rowling's series of "Harry Potter" novels.  Voldemort first appeared in "Harry Potter and the Philosopher's Stone", which was released in 1997.  Voldemort appears either in person or in flashbacks in each book and its film adaptation in the series, except the third, "Harry Potter and the Prisoner of Azkaban", where he is only mentioned.
citations: Harry Potter Lord Voldemort