Question: Which store located at 712 Fifth Avenue did Ellen Steward work at as a fashion designer in the 1950s?

Context paragraphs:
Henri Bendel: Henri Bendel, established in 1895, is an American upscale women's specialty store based in New York City that sells the Henri Bendel brand of handbags, jewelry, luxury fashion accessories, home fragrances and gifts.  Its flagship New York store is located at 712 Fifth Avenue.

Ellen Stewart: Ellen Stewart (November 7, 1919 – January 13, 2011) was an American theatre director and producer and the founder of La MaMa, E.T.C. (Experimental Theatre Club).  In the 1950s she worked as a fashion designer for Saks Fifth Avenue, Bergdorf Goodman, Lord & Taylor, and Henri Bendel.

Fulton Street (BMT Fifth Avenue Line): Fulton Street was a station on the demolished section of the BMT Fifth Avenue Line.  Served by trains of the BMT Culver Line and BMT Fifth Avenue Line, it had two tracks and one island platform.  The station was opened on July 27, 1889 at Hudson Avenue and Fulton Street, and was the northernmost Fifth Avenue Line station before the line merged with the BMT Myrtle Avenue Line.  It also had connections to the Fulton Street, DeKalb Avenue, and Flatbush Avenue Line streetcars.  The next stop to the north was Bridge–Jay Streets.  The next stop to the south was Atlantic Avenue, which still exists today as the Atlantic Avenue – Barclays Center subway station complex.  It closed on May 31, 1940.

Saint Marks Avenue (BMT Fifth Avenue Line): Saint Marks Avenue was a station on the demolished section of the BMT Fifth Avenue Line.  Served by trains of the BMT Culver Line and BMT Fifth Avenue Line, it had 2 tracks and 2 side platforms.  The station was opened on June 22, 1889 at Fifth Avenue and St. Marks Place, which is renamed St. Marks Avenue east of Fifth Avenue.  It also had a connection to the Bergen Street Line trolleys.  It closed on May 31, 1940.

Langham Place, New York: Langham Place, New York, or 400 Fifth Avenue, is a luxury suite hotel and skyscraper located in New York City.  Constructed in 2010 as The Setai Fifth Avenue and renamed in 2013.  In 2014, the 33% of the hotel was bought by Melendez International Hotels, a subsidiary of Melendez Global Inc.  The tower is located at 400 Fifth Avenue in Midtown Manhattan, in close proximity to Times Square and Grand Central Terminal.  400 Fifth Avenue was constructed using limestone in the 11-floor base in a somewhat art deco style.  Floors five through 27 contain 214 hotel rooms.

Fifth Avenue Line (Brooklyn elevated): The Fifth Avenue Line, also called the Fifth Avenue Elevated or Fifth Avenue-Bay Ridge Line, was an elevated rail line in Brooklyn, New York City, United States.  It ran above Hudson Avenue, Flatbush Avenue, Fifth Avenue, 38th Street, and Third Avenue from Downtown Brooklyn south to Bay Ridge.  The portion on Third Avenue was called the Third Avenue Elevated to distinguish service from the West End Elevated.

36th Street (BMT Fifth Avenue Line): 36th Street was a station on the demolished section of the BMT Fifth Avenue Line.  It was served by trains of the BMT Culver Line and BMT Fifth Avenue Line.  It had four tracks and two island platforms.  The station was opened on May 29, 1890, and was the southern terminus of the Fifth Avenue Line until 1893, as well as the southernmost station to be installed along Fifth Avenue itself.  Stations built beyond this point were located along Third Avenue, and the line was sometimes called the BMT Third Avenue Line south of here.  The next stop to the north was 25th Street.  The next stop to the south was Ninth Avenue for Culver Line trains and 40th Street for Fifth Avenue Line trains.  Ninth Avenue station still exists today exclusively for the BMT West End Line.  The station closed on May 31, 1940.  Current rapid transit service in this area can be found one block west at the 36th Street Station on the underground BMT Fourth Avenue Line.

Amsale Aberra: Amsale Aberra (born 1954) is an Ethiopian American fashion designer and entrepreneur.  Her main field of design is in couture wedding gowns, and her flagship store is located on Madison Avenue in New York City.  In addition to her flagship location, her gowns are also sold at fine bridal boutiques such as Saks Fifth Avenue, and Neiman Marcus.  She is a member of the Council of Fashion Designers of America (CFDA) and a Trustee of the Fashion Institute of Technology.

Richard Peacon House: The Richard Peacon House, also known as the Octagon House, is an historic octagonal house located at 712 Eaton Street (formerly 2nd Avenue) in the Old Town district of Key West, Florida.  It was built around 1885 for Richard Peacon (1840-1914), who was the owner of Key West's leading grocery store located at 800 Fleming Street and who later became a founding director of the Island City National Bank.

Fifth Avenue Transportation Company: The Fifth Avenue Transportation Company was a transportation company based in New York which was founded in 1885 and operated of horse-and-omninbus transit along Fifth Avenue, with a route running from 89th Street to Bleecker Street using horse-drawn omnibuses.  Fifth Avenue was unusual in that its residents opposed the installation of railway track for streetcars and was the only avenue in Manhattan to never see streetcar service.  The company was declared bankrupt of the earlier operator in 1896, and was succeeded by the Fifth Avenue Coach Company

Supporting paragraphs: Ellen Stewart Henri Bendel
Answer: Henri Bendel