Who led a survey party through the Cumberland Gap in the 18th century?

The correct choice is Dr. Thomas Walker, who led a survey party through the Cumberland Gap in the 18th century. Walker was a prominent figure in the early exploration of the region and is known for his role in mapping areas of Kentucky and Tennessee, which were critical to westward expansion. His expeditions and surveys also provided valuable information about the geography and natural resources of the Appalachian region, which became important for settlers and future explorations.

Daniel Boone, while a significant explorer and pioneer associated with the same area, is famous for his later expeditions and his role in settling Kentucky, but it was Thomas Walker who conducted the earlier survey of the Cumberland Gap. The other figures mentioned, such as George Washington and James Madison, were influential in American politics and military affairs but did not have specific involvement in the surveying of the Cumberland Gap like Walker did.