Question: William C. deMille and Harry Keller were both what nationalities? 

Context paragraphs:
The Night Club: The Night Club is a 1925 American comedy silent film directed by Paul Iribe and Frank Urson and written by Cecil B. DeMille, Keene Thompson, Walter Woods and William C. deMille.  The film stars Raymond Griffith, Vera Reynolds, Wallace Beery, Louise Fazenda and William Austin.  The film was released on April 27, 1925, by Paramount Pictures.

Matilda Beatrice deMille: Matilda Beatrice deMille (January 30, 1853 - October 8, 1923) (born Matilda Beatrice Samuel; also known as "Beatrice C. deMille, Agnes Graham, Tillie Samuel, Mrs. Henry deMille)" was an English-American play broker, screenwriter, playwright, theater actress and entrepreneur.  deMille was born in Liverpool, England to German Jewish parents.  She emigrated to New York with her family in 1871.  She was married to Henry deMille, an aspiring actor in Brooklyn, New York, in 1876, she had three children; her first son William C. deMille followed by Cecil B. DeMille in 1881 and daughter, Agnes Beatrice in 1891 who died four years later of spinal meningitis.

William C. deMille: William Churchill de Mille (July 25, 1878 – March 5, 1955) was an American screenwriter and film director from the silent movie era through the early 1930s.  He was also a noted playwright prior to moving into film.  Once he was established in film he specialized in adapting Broadway plays into silent films.

One More American: One More American is a 1918 American silent drama film directed by William C. deMille and written by Olga Printzlau and William C. deMille.  The film stars George Beban, Marcia Manon, Mae Giraci, Helen Jerome Eddy, Raymond Hatton, and Jack Holt.  The film was released on February 25, 1918, by Paramount Pictures.  It is not known whether the film currently survives, which suggests that it is a lost film.

William C. Morris Award: The William C. Morris YA Debut Award is an annual award given to a work of young adult literature by a "first-time author writing for teens".  It is administered by the Young Adult Library Services Association (YALSA), a division of the American Library Association (ALA).  It was named for twentieth-century American publisher William C. Morris (born 1928 or 1929 and raised up in Eagle Pass, Texas, died Sept 28, 2003 in Manhattan), whom YALSA calls an innovator and "an influential innovator in the publishing world and an advocate for marketing books for children and young adults".  The award is funded by the William C. Morris Endowment, established in 2000 and activated in 2003 with a bequest of $400,000 from the Morris estate.  Morris gave the money to ALA to fund programs, publications, events, or awards in promotion of children's literature.  In addition to being a member of ALA, Morris was the first recipient of its Distinguished Service Award in 1992.  The shortlist for the first award was announced on December 8, 2008, and the winner was announced on January 26, 2009, at the ALA's midwinter meeting.

Men and Women (1925 film): Men and Women is a lost 1925 American silent film drama produced by Famous Players-Lasky and released by Paramount Pictures.  It was directed by William C. deMille and starred Richard Dix, Claire Adams and Neil Hamilton.  It is based on a play, "Men and Women", written years earlier by David Belasco and Henry C. deMille, father of the director.

The Doctor's Secret: The Doctor's Secret is a 1929 American drama film directed by William C. deMille and written by William C. deMille.  The film stars Ruth Chatterton, H. B. Warner, John Loder, Robert Edeson, Wilfred Noy and Ethel Wales.  It is based on a play by J. M. Barrie.  The film was released on January 26, 1929, by Paramount Pictures.

Harry Keller: Harry Keller (22 February 1913 – 19 January 1987) was an American film editor, producer and director, who made a number of westerns and worked for many years at Universal Pictures.  He is perhaps best remembered today for shooting additional footage on "Touch of Evil" (1958).

Mae Giraci: Mae Georgia Giraci (22 January 1910 – 10 January 2006), also known as May Giraci, May Garcia, May Geraci, May Giracci, May Giracia and Tina Rossi, was an American child actress who appeared in silent films between 1915 and 1929.  She was discovered by director Cecil B. DeMille and worked with him and his brother William C. DeMille.  She died of colon cancer in 2006.

Commando Cody: Sky Marshal of the Universe: Commando Cody: Sky Marshal of the Universe (or, informally, Commando Cody) is a 1953 Republic Pictures black-and-white multi-chapter movie serial, which began life as a proposed syndicated television series.  It consisted of twelve 25-minute sequential episodes directed by Harry Keller, Franklin Adreon, and Fred C. Brannon, that stars Judd Holdren, Aline Towne, Gregory Gaye, William Schallert, Richard Crane, and Craig Kelly.

Supporting paragraphs: Harry Keller William C. deMille
Answer: American