Question: Who is the eldest daughter of a quartet formed during WWII?

Context paragraphs:
Tetzlaff Quartett: The Tetzlaff Quartett is a German string quartet formed in 1994.  To date the quartet has released three CD recordings, of which their 2014 recording of Berg's Lyric Suite and the Mendelssohn Quartet Op. 13 received a Diapasons d'Or award and was an Editor's Choice for Gramophone Magazine

Emerson String Quartet: The Emerson String Quartet, also known as the Emerson Quartet, is a professional string ensemble – in residence at the Stony Brook University.  The musical ensemble was previously in residence at The Hartt School located in West Hartford, Connecticut.  Choosing American poet and philosopher Ralph Waldo Emerson as namesake, the quartet formed at the Juilliard School as a student ensemble.  They turned professional in 1976, with both of their violinists having studied under the tutelage of the renowned Oscar Shumsky, alternating as first and second violinists.  When it was formed, the Emerson Quartet was one of the first with the two violinists alternating chairs.

Lough Gill Quartet: The Lough Gill Quartet was an Irish Traditional Music Quartet formed in Dublin, Ireland in the 1930s.  The quartet was named after the famous Sligo lake and as a tribute to Michael Coleman who came from Sligo.

New Orford String Quartet: The New Orford String Quartet is a Canadian string quartet formed in July 2009.  It is one of Canada's premiere chamber ensembles.  The name honors the Orford Arts Centre in the province of Quebec, where the ensemble gave its first public concert, and the original Orford String Quartet that was formed in June 1965 and active until July 1991.

Earl de Grey: Earl de Grey, of Wrest in the County of Bedford, was a title in the Peerage of the United Kingdom.  It was created on 25 October 1816 (as Countess de Grey) for Amabell Hume-Campbell, Dowager Lady Polwarth and "suo jure" 5th Baroness Lucas, with remainder to the heirs male of her body and in default of such issue to her sister Mary Jemima Robinson, Dowager Baroness Grantham, and the heirs male of her body.  She was the eldest daughter and co-heir of Philip Yorke, 2nd Earl of Hardwicke, and Jemima Yorke, 2nd Marchioness Grey (see Marquess Grey), eldest daughter of John Campbell, 3rd Earl of Breadalbane and Holland, and Lady Amabel Grey, eldest daughter of Henry Grey, 1st Duke of Kent (see Duke of Kent).  The marquessate of Grey had become extinct on her mother's death in 1797 and when the Grey title was revived in favour of her daughter the style "de Grey" was used to distinguish it from the earldom of Grey which had been created in 1806; the Grey family was extremely distantly related to the Earl Grey).  The Countess de Grey was the widow of Alexander Hume-Campbell, Lord Polwarth, eldest son of Hugh Hume, 3rd Earl of Marchmont.

Orion String Quartet: The Orion String Quartet is a string quartet formed in 1987.  It is the quartet-in-residence of The Chamber Music Society of Lincoln Center and New York's Mannes College The New School for Music.  The members are Todd and Daniel Phillips, brothers who alternate on first and second violin, violist Steven Tenenbom and cellist Timothy Eddy.  Members of the quartet teach at the Curtis Institute of Music, Mannes, Juilliard, Queens College, and the Bard College Conservatory of Music.

The Carter Sisters: The Carter Sisters, (also known as the second version of The Carter Family) were an American singing quartet consisting of Maybelle Carter and her daughters June Carter Cash, Helen Carter, and Anita Carter.  Formed during World War II, the group recorded and performed into the 1990s.

New World String Quartet: The New World String Quartet was a classical music string quartet formed in the city of Grand Rapids, Michigan, United States, in 1975 and active through the early 1990s.  Founding members were: Yosef Yankelev and William Patterson, violins; Yuri Vasilaki, viola; and Ross Harbaugh, cello.  These were also the members in a 1981 Minnesota Public Radio interview and performance.  As of 1983, members were: Curtis J. Macomber and William Patterson, violins; Robert Dan, viola; and Ross T. Harbaugh, cello.  These are also the members listed on the quartet's recording of Ben Johnston's

Zagreb Quartet: The Zagreb Quartet ("Zagrebački Kvartet"), also known as the Zagreb String Quartet ("Zagrebački Gudački Kvartet") is a Zagreb–based string quartet formed in 1919.  The oldest Croatian chamber ensemble, they have played at more than 3,000 concerts on all continents, recorded more than 60 albums and won numerous domestic and foreign awards, including the Vladimir Nazor Award for lifetime achievement in 2009.

Helen Carter: Helen Myrl Carter (September 19, 1927 – June 2, 1998) was an American country music singer.  The eldest daughter of Maybelle Carter, she performed with her mother and her younger sisters, June Carter and Anita Carter, as a member of "Mother Maybelle and the Carter Sisters", a pioneering all female country/folk music group.  The group was also known as The Carter Family.

Supporting paragraphs: The Carter Sisters Helen Carter
Answer: Helen Carter