premise: Phoebe Snow was a fictional character created by Earnest Elmo Calkins to promote the Delaware, Lackawanna and Western Railroad. The advertising campaign was one of the first to present a fictional character based on a live model amid impressionistic techniques.
hypothesis: Phoebe Snow's character was created by one person.
reason: Phoebe Snow's character was created by one person is definitely correct because it is mentioned the creator  Earnest Elmo Calkins in the statement.