Question: Which American film director was also a choreographer, Bob Fosse or Joseph Ruben?

Context paragraphs:
American Choreography Awards: The American Choreography Awards was a ceremony and show that honored outstanding choreographers in the fields of feature film, television, music videos, and commercials.  They were first known as the L.A. Dance Awards (1994–95), then as Bob Fosse Awards, and a.k.a. Fosse’s (1996–97), and eventually the American Choreography Awards (1998-'04).  Each year in the fall, they were held at a different location in Los Angeles, California.  These include places such as the Orpheum Theatre, El Capitan Theatre, Alex Theatre, Wilshire Ebell Theatre, The Hollywood Palace, The Museum of Flying, The Century Club, and Club Tatou.

Dreamscape (1984 film): Dreamscape is a 1984 American science-fiction adventure horror film directed by Joseph Ruben and written by David Loughery, with Chuck Russell and Ruben co-writing.

Gwen Verdon: Gwyneth Evelyn “Gwen” Verdon (January 13, 1925 – October 18, 2000) was an American actress and dancer.  She won four Tony awards for her musical comedy performances and served as uncredited choreographers assistant and specialty dance coach for both theater and film.  With flaming red hair and a quaver in her voice, Verdon was a critically acclaimed performer on Broadway in the 1950s, 1960s, and 1970's.  Having originated many roles in musicals she is also strongly identified with her second husband, director–choreographer Bob Fosse, remembered as the dancer–collaborator–muse for whom he choreographed much of his work and as the guardian of his legacy after his death.

Bob Fosse: Robert Louis Fosse (June 23, 1927 – September 23, 1987) was an American dancer, musical theatre choreographer, director, screenwriter, film director and actor.

All That Jazz (song): "All That Jazz" (alternatively "And All That Jazz") is a song from the 1975 musical "Chicago".  It has music by John Kander and lyrics by Fred Ebb, and is the opening song of the musical.  The title of the 1979 film, starring Roy Scheider as a character strongly resembling choreographer/stage and film director Bob Fosse, is derived from the song.

Kathryn Doby: Kathryn Doby is an American dancer, actresses, choreographer, and assistant to Bob Fosse.  She made her Broadway debut in the ensemble of Fosse’s "Sweet Charity" in January 1966 at the Palace Theatre in Times Square.  Aside from her performance in the musical "Gregory" (1970), Doby’s work on Broadway continued with Fosse as a Player and Dance Captain in "Pippin" (1972) and as an assistant to Mr. Fosse for "Chicago" (1975) and "Dancin’" (1978).  Her film credits include "The Night They Raided Minsky's" - “Minsky Girl” (1968), "The Handmaid's Tale (film)" - Aunt Elizabeth (1990), and again worked with Fosse as a dancer in "Sweet Charity" (1969), "Cabaret" – Kit Kat Dancer (1972), and "All That Jazz" – Kathryn (1979).  She also re-set the Fosse direction and choreography for the 1981 stage production of "Pippin", starring Ben Vereen, William Katt, and Chita Rivera that was filmed for TV.  She was also slated to recreate the choreography for "Dancin" to be revived by the Roundabout Theatre Company in 2009.  This production was postponed and, as of the date of this entry, does not have a projected start date.  In 2012 Doby returned to New York from her home in California to restage the "Dancin’" Act One finale, “Beat Me Daddy Eight to the Bar” for the American Dance Machine for the 21st Century (ADM21).  She was joined by original cast members Lloyd Culbreath, Valarie Pettiford, Cady Huffman, Roumel Reaux, and Candace Tovar.

Joseph Ruben: Joseph Porter Ruben (born May 10, 1950) is an American film director, screenwriter and producer.

The Pom Pom Girls: The Pom Pom Girls (also known as Palisades High) is a 1976 film directed by Joseph Ruben.  The screenplay was written by Ruben and based on a story by him and Robert J. Rosenthal.  The movie was shot on location at Chaminade High School in Los Angeles.

Liza with a Z: Liza with a "Z": A Concert for Television is a 1972 concert film, made for television and starring Liza Minnelli.  The film was produced by Fred Ebb and Bob Fosse.  As well as producing, Fosse also directed and choreographed the concert, and Ebb wrote and arranged the music with his song-writing partner John Kander.  All four had previously worked on the successful film adaptation of "Cabaret" earlier in the same year.  According to Minnelli, it was "the first filmed concert on television".  Singer sponsored the production, even though the producers did their best to keep any of the sponsors from seeing the rehearsals for fear of them pulling out due to Minnelli's short skirts.

All That Jazz (film): All That Jazz is a 1979 American musical drama film directed by Bob Fosse.  The screenplay by Robert Alan Aurthur and Fosse is a semi-autobiographical fantasy based on aspects of Fosse's life and career as dancer, choreographer and director.  The film was inspired by Fosse's manic effort to edit his film "Lenny" while simultaneously staging the 1975 Broadway musical "Chicago".  It borrows its title from the Kander and Ebb tune "All That Jazz" in that production.  The film won the Palme d'Or at the 1980 Cannes Film Festival.

Supporting paragraphs: Bob Fosse Joseph Ruben
Answer: Robert Louis Fosse