What type of performance art emerged in the 1870s, featuring comic sketches and song-and-dance routines?

Vaudeville is the correct choice because it refers specifically to a theatrical variety show popular in the United States during the late 19th and early 20th centuries. This form of entertainment combined diverse acts, including comic sketches, dance numbers, and musical performances, creating a lively and dynamic experience for audiences. Vaudeville shows typically featured multiple acts in a single performance, allowing various forms of entertainment to shine, which was distinct from other types of performance art.

Musical theatre, while it does include song and dance, typically focuses more on a cohesive narrative structure and storytelling than the variety format of vaudeville. Opera, on the other hand, emphasizes classical music and vocal performance, often lacking the comedic and casual nature associated with vaudeville acts. Burlesque, while it can incorporate elements of parody and comedy, is generally more focused on satire and adult humor, differing from the broader variety nature that defines vaudeville.