Which musical is considered the first full-fledged Broadway musical by Kern and Hammerstein?

The first full-fledged Broadway musical by the team of Jerome Kern and Oscar Hammerstein II is "Showboat." This musical premiered in 1927 and is significant for several reasons. It is lauded for its integration of music, story, and character development, setting a new standard for American musical theater.

"Showboat" was revolutionary for its time, as it addressed serious themes such as racial prejudice and complex human relationships, which were largely absent from musicals prior to its release. It also featured a more cohesive and dramatic narrative structure, where the songs were not merely interludes but integral to the story, enhancing the emotional depth of the characters and the overall arc of the production.

This groundbreaking approach established certain conventions that would become common in later musicals, making "Showboat" a critical piece of theater history and solidifying Kern and Hammerstein's influence on the genre. The other options, while notable works in their own right, came after "Showboat" and did not mark the same paradigm shift in musical theater that "Showboat" did.