Question: Which artists are responsible for the sculpture permanently installed northwest of Valentine, Texas and about 26 miles northwest of a city in the high desert of the Trans-Pecos, located between the Davis Mountains and Big Bend National Park?

Context paragraphs:
Marfa, Texas: Marfa is a city in the high desert of the Trans-Pecos in far West Texas, located between the Davis Mountains and Big Bend National Park.  It is the county seat of Presidio County, and its population as of the 2010 United States Census was 1,981.  The city was founded in the early 1880s as a water stop; the population increased during World War II, but the growth stalled and reversed somewhat during the late 20th century.  Today, Marfa is a tourist destination and a major center for Minimalist art.  Attractions include Building 98, the Chinati Foundation, artisan shops, historical architecture, a classic Texas town square, modern art installments, art galleries, and the Marfa lights.

Homer Wilson Ranch: The Homer Wilson Ranch, also known as the Blue Creek Ranch, was one of the largest ranches in the early twentieth century in what would become Big Bend National Park in the U.S. state of Texas.  The ranch was established by Homer Wilson in 1929 at Oak Springs to the west of the Chisos Mountains.  Ultimately comprising 44 sections of land, amounting to more than 28000 acre , the Oak Canyon-Blue Creek Ranch was acquired by the State of Texas in 1942 for incorporation into the new park.  A large portion of the ranch comprised portions of the old G4 Ranch (named after Survey Block G4), established by John and Clarence Gano in the 1880s.  Wilson's ranch focused on sheep and goats, the first such large operation in the Big Bend area.  Wilson continued to live at the ranch until his death in 1943; his family moved from the ranch the next year.  Wilson, born in Del Rio, Texas in 1892, had studied petroleum engineering at the Missouri School of Mines and was a World War I veteran.  The ranch, with the headquarters at Oak Springs and its operational center at Blue Creek, was one of the largest in Texas, and the most significant ranch in Big Bend.

Gundlachia triantha: Gundlachia triantha, the TransPecos goldenshrub or Trans-Pecos desert goldenrod, is a North American species of plants in the sunflower family.  It is native to northern Mexico (Chihuahua, Coahuila, Durango, Nuevo León), with the range extending just over the Río Grande into western Texas in and near Big Bend National Park.

Prada Marfa: Prada Marfa is a permanently installed sculpture by artists Elmgreen and Dragset, situated 2.3 km northwest of Valentine, Texas, just off U.S. Highway 90 (US 90), and about 26 mi northwest of the city of Marfa.  The installation was inaugurated on October 1, 2005.  The artists called the work a "pop architectural land art project."

U.S. Route 385 in Texas: U.S. Route 385 (US 385) is a north-south U.S. highway that runs from Big Bend National Park in Texas to Deadwood, South Dakota.  In Texas, the highway runs from Big Bend National Park to the Oklahoma state line, north of Dalhart.

Texas State Highway 118: State Highway 118, or SH 118, is a 155.3 mi state highway in the U.S. state of Texas that runs from Big Bend National Park north to Kent and passes through the towns of Study Butte, Alpine, and Fort Davis.  SH 118 is maintained by the Texas Department of Transportation (TxDOT).  The road lies entirely within the Trans-Pecos region of Texas.  SH 118 is a two-lane road along its length except for a section in Alpine where the route follows the path of U.S. Route 67 and U.S. Route 90.  All of the route except for the 2.8 mi section between Big Bend National Park and Farm to Market Road 170 is included in the Texas Historical Commission's Texas Mountain Trail.

Big Bend gambusia: The Big Bend gambusia ("Gambusia gaigei") is a rare species of fish in the Poeciliidae family.  It is endemic to the Big Bend region of the Rio Grande of the United States and Mexico.  The only known remaining population is in a protected pond in the Big Bend National Park.

Trans-Pecos: The Trans-Pecos, as originally defined in 1887 by the Texas geologist Robert T. Hill, is the portion of Texas that lies west of the Pecos River.  The term is considered synonymous with "Far West Texas", a subdivision of West Texas.  The Trans-Pecos is part of the Chihuahuan Desert, the largest desert in North America.  It is the most mountainous and arid portion of the state, and most of its area (outside the city of El Paso) is vast and sparsely populated, comprising seven of the ten largest counties by area in Texas.  The area is known for the natural environment of the Big Bend and the gorge of the Rio Grande, part of which has been designated a National Wild and Scenic Rivers System.  With the notable exceptions of Big Bend Ranch State Park and Big Bend National Park, the vast majority of the Trans-Pecos region consists of privately owned ranchland.  The vast majority of the region's population reside in the El Paso metropolitan area.

Chisos Mountains: The Chisos Mountains are a mountain range located in the Big Bend area of West Texas, United States.  The mountain range is contained entirely within the boundaries of Big Bend National Park.  This is the only mountain range in the United States to be fully contained within the boundary of a national park.  It is also the southernmost mountain range in the mainland United States.

Acleisanthes parvifolia: Acleisanthes parvifolia, common names littleleaf moonpod and Big Bend trumpets, is a plant species native to northeastern Chihuahua and western Texas.  In Texas, is known from only 4 counties: Culberson, Hudspeth, Brewster and Presidio.  Some of the populations are situated inside Big Bend National Park, others within Guadalupe Mountains National Park.

Supporting paragraphs: Prada Marfa Marfa, Texas
Answer: Elmgreen and Dragset