Triple

Target entity: Langdon Clemens
Context triple: [Olivia Susan Clemens, sibling, Langdon Clemens]

• A. Langdon Clemens chosen
  Langdon Clemens was the firstborn son of American author Mark Twain (Samuel Clemens), who died in infancy.
• B. Stephen Johnson Field
  Stephen Johnson Field was an influential 19th-century American jurist who served as an Associate Justice of the U.S. Supreme Court from 1863 to 1897, shaping constitutional law during the post–Civil War and Gilded Age eras.
• C. John Mead Howells
  John Mead Howells was an American architect best known for his influential skyscraper designs in the early 20th century and his role in shaping Chicago’s and New York’s urban skylines.
• D. William Beecher
  William Beecher was a member of the prominent 19th-century Beecher family, known for its influential religious and social reform figures in American history.
• E. Charles Dudley Warner
  Charles Dudley Warner was a 19th-century American essayist and novelist best known for co-authoring "The Gilded Age: A Tale of Today" with Mark Twain, which gave its name to the era of rapid economic growth and social inequality in post–Civil War America.
• F. None of above.
• G. Unsure - the case is ambiguous/there is not enough information to decide.