Question: Which film director is best known for the movie "Alvin Purple", Mark Robson or Tim Burstall?

Context paragraphs:
David Garrett (screen writer): David Garrett is an American filmmaker best known for directing and producing the feature-length documentary film "Who is Alvin Greene?" , following South Carolina's unlikely Democratic nominee for the U.S. Senate Alvin Greene on the 2010 campaign trail.  The film is co-directed and co-produced by Leslie Beaumont.  Garrett also co-wrote the 2005 comedy film and the 2001 comedy Corky Romano

The Inn of the Sixth Happiness: The Inn of the Sixth Happiness is a 1958 DeLuxe Color 20th Century Fox CinemaScope film based on the true story of Gladys Aylward, a tenacious British maid, who became a missionary in China during the tumultuous years leading up to World War II.  Directed by Mark Robson, who received an Academy Award for Best Director nomination, the film stars Ingrid Bergman as Aylward and Curt Jürgens as her love interest, Colonel Lin Nan, a Chinese officer with a Dutch father.  Robert Donat, who played the mandarin of the town in which Aylward lived, died before the film was released.  The musical score was composed and conducted by Malcolm Arnold.  The cinematography was by Freddie Young.

Stork (film): Stork is a 1971 Australian comedy film directed by Tim Burstall.  "Stork" is based on the play "The Coming of Stork" by David Williamson.  Bruce Spence and Jacki Weaver make their feature film debuts in "Stork", being honoured at the 1972 Australian Film Institute Awards, where they shared the acting prize.  "Stork" won the prize for best narrative feature and Tim Burstall won for best direction.  Stork was one of the first ocker comedies.  "Stork" was the first commercial success of the Australian cinema revival called the Australian New Wave.

Bostock's Cup: Bostock's Cup was a one-off British television comedy drama about a football team which appeared on ITV on the eve of the 1999 European Cup final.  It was written by Chris England, directed by Marcus Mortimer and produced by Mark Robson.  It starred Tim Healy as the club's manager, Neil Pearson as a veteran sportscaster, and Nick Hancock as his upstart rival.  The film featured innovative use of old footage of seventies football matches to recreate the era.  It was aired on 25 May 1999.

Trial (1955 film): Trial is a 1955 American film directed by Mark Robson based on the novel written by Don Mankiewicz.  It stars Glenn Ford, Dorothy McGuire, Arthur Kennedy, and Juano Hernandez.  It is about a Mexican boy accused of rape and murder; originally victimized by prejudiced accusers, he becomes a pawn of his communist defender, whose propaganda purposes would be best served by a verdict of guilty.

I Want You (1951 film): I Want You is a 1951 film directed by Mark Robson taking place in America during the Korean War.  The film was nominated for the Academy Award for Best Sound (Gordon E. Sawyer).

Alvin Purple: Alvin Purple is an 1973 Australian comedy film starring Graeme Blundell, written by Alan Hopgood and directed by Tim Burstall.

Mark Robson: Mark Robson (4 December 1913 – 20 June 1978) was a Canadian-born film director, producer and editor.  Robson began his 45-year career in Hollywood as a film editor.  He later began working as a director and producer.  He directed thirty-four films during his career including "The Bridges at Toko-Ri" (1955), "Peyton Place" (1957), for which he earned his first Academy Award nomination, "Von Ryan's Express" (1965) and "Valley of the Dolls" (1967).

Alvin Rides Again: Alvin Rides Again is a 1974 Australian sex-comedy film sequel to "Alvin Purple".  It was directed by David Bilcock and Robin Copping, who were regular collaborators with Tim Burstall.  It was rated M unlike its predecessor which was rated R. "Alvin Rides Again" still features a lot of full frontal nudity.

Tim Burstall: Timothy "Tim" Burstall AM (20 April 1927 – 19 April 2004) was an English Australian film director, writer and producer, best known for hit Australian movie "Alvin Purple" (1973) and its sequel "Alvin Rides Again".

Supporting paragraphs: Mark Robson Tim Burstall
Answer: Timothy "Tim" Burstall AM