Final answer:
Vaudeville variety shows before Broadway consisted of all of the above options: musical performances, comedy sketches, and a variety of other acts, becoming a cornerstone of American entertainment at the time.
Step-by-step explanation:
Vaudeville variety shows were a fusion of numerous types of performances that existed before Broadway became prominent. These shows were largely popular at the turn of the 20th century and provided a mixed entertainment experience. Therefore, the correct answer to what vaudeville variety shows included before Broadway is d) All of the Above, as they incorporated musical performances, comedy sketches, and a wide range of variety acts. Vaudeville was a platform for many forms of entertainment and hosted an array of acts including singers, dancers, magicians like Harry Houdini, and burlesque acts. Even brief film clips were shown in these variety shows, which later evolved and contributed to the rise of modern movie theaters.