Triple

Given a phrase, classify it is english named entity (e.g., persons, organizations, works of art) in Latin script, or not (e.g., literals, dates, URLs, verbose phrases). For disambiguation, the statement where the phrase occurs as object is also given. Please return a JSON object with `phrase` (string, the phrase being analyzed) and `is_ne` (boolean, indicating whether the phrase is a Named Entity).

Phrase: United States northern frontier | Statement: [Convention of 1818, affectedRegion, United States northern frontier]

Target entity: United States northern frontier
Context triple: [Convention of 1818, affectedRegion, United States northern frontier]

• A. Frontier (North America)
  Frontier (North America) is the name used in the North American market for Nissan's mid-size pickup truck line.
• B. Indian Territory
  Indian Territory was a region in the United States, primarily in present-day Oklahoma, that served as a government-designated area for the forced relocation and settlement of numerous Native American tribes during the 19th century.
• C. Northwest Territory chosen
  The Northwest Territory was a vast early United States territory established after the American Revolution, encompassing lands that later became the states of Ohio, Indiana, Illinois, Michigan, Wisconsin, and part of Minnesota.
• D. Territory South of the River Ohio
  The Territory South of the River Ohio was a late 18th-century U.S. territorial government, commonly known as the Southwest Territory, that preceded the statehood of Tennessee.
• E. Northern Frontier
  Northern Frontier is a themed exhibit area at the San Diego Zoo that showcases cold-climate animals such as polar bears and other Arctic species.
• F. None of above.
• G. Unsure - the case is ambiguous/there is not enough information to decide.