Question: The Elk River's headwaters end at which large stream of western North Carolina and East Tennessee?

Context paragraphs:
Watauga River: The Watauga River is a large stream of western North Carolina and East Tennessee.  It is 78.5 mi long with its headwaters on the slopes of Grandfather Mountain and Peak Mountain in Watauga County, North Carolina.

Elk River (Colorado): Elk River is a 34.2 mi stream in Colorado.  It flows from a confluence of the North Fork Elk River and Middle Fork Elk River in Routt National Forest north of Steamboat Springs to a confluence with the Yampa River.

Jason Sabbides: Jason Sabbides (born 1976) is an American artist from Springfield, Massachusetts.  Sabbides has received a Bachelor of Fine Arts from The University of North Carolina at Asheville in 2008, and his Master of Fine Arts from East Tennessee State University in 2012.  He started creating art in 2004 after he left the army.  He was a professor at East Tennessee State University and an adjunct professor of art at Virginia Highlands Community College.  He is currently Assistant Professor of Art and Design at Lees-McRae College, in Banner Elk, North Carolina.  Sabbides dabbles in all art media from painting,to printmaking and sculpture.

Tweetsie Railroad: Opened in 1957, Tweetsie Railroad began as an excursion train ride pulled by steam locomotive #12, the only surviving narrow gauge engine of the East Tennessee and Western North Carolina Railroad (ET&WNC).  Built in 1917 by the Baldwin Locomotive Works, #12 is a narrow gauge 4-6-0 coal-fired locomotive that was used from 1918 to 1940 to haul passengers and freight over the ET&WNC's 66 mi line running through the Appalachian Mountains from Johnson City to Boone, North Carolina.  The name "Tweetsie" was given to the original East Tennessee and Western North Carolina Railroad by area residents who became accustomed to the shrill "tweet, tweet" of the train whistles that echoed through the mountains.  The nickname stuck with the railroad and its trains, and became more identifiable than the railroad's original name.

Elk River (North Carolina–Tennessee): The Elk River is a large stream in the North Carolina High Country and East Tennessee.  The headwaters begin from the Northwestern slopes of Peak Mountain in Avery County, North Carolina and end at the Watauga River in Carter County, Tennessee.

Maryland Route 272: Maryland Route 272 (MD 272) is a state highway in the U.S. state of Maryland.  The state highway runs 20.67 mi from Turkey Point within Elk Neck State Park north through North East to the Pennsylvania state line near Calvert, where the highway continues as Pennsylvania Route 272 (PA 272).  MD 272 is the main north–south highway of central Cecil County, connecting the Elk Neck between the North East River and Elk River with U.S. Route 40 (US 40) and Interstate 95 (I-95) in North East, MD 273 in Calvert, and Rising Sun via MD 274.  The section of MD 272 between North East and Bay View was paved by 1910.  The remainder of the state highway north to Calvert and south to Elk Neck was completed in several sections in the 1930s.  The first relocations of MD 272 occurred when both railroads near North East were bridged in the early 1940s and mid-1950s.  Multiple relocations occurred in the late 1950s and early 1960s along the whole length of the highway to eliminate curves and tie the state highway into I-95.  MD 272 reached its current extent when it was extended south into Elk Neck State Park in 1979.

Shawneehaw Creek: The Shawneehaw Creek is a stream in the North Carolina High Country and is named after a Cherokee word for a tree that blooms early in the Spring, the current name for the tree is Serviceberry, or sarvisberry, and is located in the town of Banner Elk.  The headwaters begin from the Southeastern slopes of Beech Mountain in Watauga County, North Carolina and end at the Elk River in Avery County, North Carolina. The tree extend from North Carolina to Louisiana and Florida, and to 6000 feet.

Middle Fork Elk River: Middle Fork Elk River is a 3.5 mi stream in Colorado.  It flows from a confluence of Gilpin Creek and Gold Creek in Routt National Forest north of Steamboat Springs to a confluence with the North Fork Elk River that forms the Elk River

South Fork Elk River: The South Fork Elk River is a 13.5 mi stream in Colorado in the United States.  It flows from a source near Dome Lake in Routt National Forest north of Steamboat Springs to a confluence with the Elk River.

Webster Sycamore: The Webster Sycamore (alternatively known as the Webster Springs Sycamore and the Big Sycamore Tree) was an American sycamore ("Platanus occidentalis") in the U.S. state of West Virginia.  Long recognized for its size, the Webster Sycamore was the largest living American sycamore tree in West Virginia until its felling in 2010.  The tree stood approximately 4.5 mi east of Webster Springs in Webster County, in a moist flood plain along the banks of the Back Fork Elk River, a tributary stream of the Elk River.

Supporting paragraphs: Elk River (North Carolina–Tennessee) Watauga River
Answer: Watauga River