Which of the following artists is known for their contribution to Appalachian folk music?

Bill Monroe is widely recognized as a pivotal figure in the development of Appalachian folk music, particularly for his role in popularizing bluegrass—a genre that is deeply rooted in Appalachian traditions. His innovative approach combined elements of traditional folk, blues, and jazz to create a distinctive sound characterized by the use of mandolin, banjo, fiddle, and guitar. Monroe's band, the Blue Grass Boys, launched the genre into national prominence and influenced countless musicians. His songs often reflect the themes, stories, and culture of the Appalachian region, making him an integral part of its musical heritage. This foundation of his work has solidified his reputation as the "Father of Bluegrass," linking him directly to the broader context of Appalachian folk music.