Final answer:
At the turn of the century, 'ragtime' referred to a piano style, a type of song, and a syncopated dance. It is characterized by 'ragged' rhythms and a strong beat which led to the evolution of jazz music. Scott Joplin was a central figure in spreading the popularity of ragtime with compositions like 'Maple Leaf Rag'.
Step-by-step explanation:
At the turn of the century, the term "ragtime" meant d. all of the above: a piano style, a type of song, and a syncopated dance. Ragtime is a uniquely American form of music that featured "ragged" rhythms and a strong beat. The structure of ragtime flouted conventional theories about music of that era, inspiring improvisation and giving birth to other forms of music such as jazz. Scott Joplin, an African American composer, became the most famous figure associated with ragtime. His compositions, such as "Maple Leaf Rag", were spread by the sale of sheet music, leading to the widespread popularity of ragtime across America. The genre originated from the blend of black spirituals with Euro-American folk music and had deep roots in the interracial dance halls of the red-light districts of the Deep South.