Question: The western border of Rankin County is formed by a river that flows through which US states ?

Context paragraphs:
Ireng River: The Ireng River (or Maú River) forms part of Guyana's western border with Brazil.  It flows through the valleys of the Pakaraima Mountains for most of its length.  It is the only major river in Guyana which flows from North to South.  It is one of the northernmost tributaries of the Amazon river system.

Río Verde (Oaxaca): The Río Verde is a river in the state of Oaxaca in Mexico.  It is formed by the confluence of the Atoyaquillo and Colorado Rivers near the village of Santiago Ixtayutla and flows south to its mouth at El Azufre on the Pacific Ocean, on the western border of Lagunas de Chacahua National Park.  Its major tributary is the Atoyac, which drains the Oaxaca Valley and flows into the Río Verde at Paso de la Reina, where a proposal to build a large hydroelectric dam project has been opposed by local communities.  The combined length of the Atoyac and lower Verde rivers is 342 km and the river system as a whole drains a watershed of 18812 km2 , which has a mean natural surface runoff of 6046 hm3 per year.  The watershed covers almost a fifth of Oaxaca state and is home to over a third of its population, and faces serious degradation issues as a result of pollution and overexploitation.

Mucone: The Mucone is a river in the province of Cosenza, Calabria, southern Italy.  The source of the river is in La Sila north of Botte Donato.  It flows into Lago di Cecita and flows out of the lake near the western border of Sila National Park.  The river flows northwest before curving west near Acri.  It flows near Bisignano before flowing into the Crati east of Torano Castello.  The Mucone is the largest right tributary of the Crati.

Muscogee County, Georgia: Muscogee County is a county located on the central western border of the U.S. state of Georgia; its western border with the state of Alabama is formed by the Chattahoochee River.  As of the 2010 census, the population was 189,885.  Its county seat and only city is Columbus, with which it has been a consolidated city-county since the beginning of 1971.

Baleshwari River: The Baleshwari River is located in Bangladesh, forming part of the eastern border of Bagerhat District and the western border of Barguna District.  It borders on the east the largest mangrove forest in the world, in the Ganges-Brahmaputra delta, the Bangladesh part of which is set aside as the Sundarbans Reserve Forest.  The Baleshwar River flows south into the Haringhata River, which flows into the Bay of Bengal.

Columbia River: The Columbia River is the largest river in the Pacific Northwest region of North America.  The river rises in the Rocky Mountains of British Columbia, Canada.  It flows northwest and then south into the US state of Washington, then turns west to form most of the border between Washington and the state of Oregon before emptying into the Pacific Ocean.  The river is 1243 mi long, and its largest tributary is the Snake River.  Its drainage basin is roughly the size of France and extends into seven US states and a Canadian province.  The fourth-largest river in the United States by volume, the Columbia has the greatest flow of any North American river entering the Pacific.

Zhuoshui River: The Zhuoshui River, also spelled Choshui River, () is the longest river in Taiwan.  It flows from its source in Nantou County up to the western border of the county, subsequently forming the border between Yunlin County and Changhua County, with a total length of 186 km.

Pearl River (Mississippi–Louisiana): The Pearl River is a river in the U.S. states of Mississippi and Louisiana.  It forms in Neshoba County, Mississippi from the confluence of Nanih Waiya and Tallahaga creeks.  and has a meander length of 444 mi .  The lower part of the river forms part of the boundary between Mississippi and Louisiana.  The river contains large areas of bottomland hardwood swamp and cypress swamp, providing habitat for many species of wildlife including sturgeon and black bears.  There was once hope that Ivory-billed woodpeckers might survive here, but this now seems unlikely.  The mouth of the river provides important marsh habitat along salinity gradients; these marshes have been the subject of many scientific studies.  It is considered to be one of the most critical areas of natural habitat remaining in Louisiana.  The Mississippi state capital, Jackson, is located on the river.

Rankin County, Mississippi: Rankin County is a county located in the U.S. state of Mississippi.  The western border of the county is formed by the Pearl River.  As of the 2010 census, the population was 141,617, making it the fourth-most populous county in Mississippi.  The county seat is Brandon.  The county is named in honor of Christopher Rankin, a Mississippi Congressman who served from 1819 to 1826.

Kadalundi River: Kadalundi River (Kadalundipuzha) is one of the four most important rivers flowing through Malappuram district in the Indian state of Kerala.  The other three are the Chaliyar, the Bharathappuzha and the Tirur River.  This rain-fed river is 110 km long and is one of the most important rivers in the district.  It is formed by the confluence of the Olipuzha River and the Veliyar River. The Kadalundi originates from the Western Ghats at the western border of the Silent Valley and flows through the district of Malappuram.  It has two main tributaries namely Olipuzha and Veliyar.  The Kadalundi River drains an area of 1274 km² and has a length of 120 km.  The Kadalundi Bird Sanctuary spreads over a cluster of islands where the Kadalundipuzha River flows into the Arabian Sea.  There are over a hundred varieties of native birds and around 60 varieties of migratory birds that come here in large numbers annually.

Supporting paragraphs: Rankin County, Mississippi Pearl River (Mississippi–Louisiana)
Answer: Mississippi and Louisiana