Question: Which borders Vietnam, Hekou Yao Autonomous County or Lhasa City?

Context paragraphs:
Jinxiu Yao Autonomous County: Jinxiu () is a county of eastern Guangxi, China, located in an area of relatively high concentrations of the Yao people.  It is administered as the Jinxiu Yao Autonomous County of Laibin City.  Established in 1952, with the name of Dayaoshan Autonomous Zone, in 1966, it was renamed as Jinxiu Yao Autonomous County.  It has an area of 2517 km2 , much of it mountainous, and a population in 2004 of approximately 150,000.

Hekou North Railway Station: Hekou North Railway Station () is a railway station in Hekou Town, the county seat of Hekou Yao Autonomous County in Yunnan Province of China.  It is the southern end of the standard-gauge Kunming–Yuxi–Hekou Railway.  It also is connected by meter-gauge tracks to the meter-gauge Kunming–Hekou Railway (the Chinese section of the international Kunming–Hai Phong Railway), thus serving as a linking point between Vietnam's meter-gauge rail network and China's standard-gauge network.

Jianghua Yao Autonomous County: Jianghua ( ""Jianghua Yao Autonomous County"", ; usually referred to as ""Jianghua County"", ) is an autonomous county of Yao people in the Province of Hunan, China, it is under the administration of Yongzhou Prefecture-level City.

Lhasa (prefecture-level city): Lhasa City is a prefecture-level city, formerly a prefecture until 7 January 1960, one of the main administrative divisions of the Tibet Autonomous Region of China.  It covers an area of 29274 km2 of rugged and sparsely populated terrain.

Gracixalus jinxiuensis: Gracixalus jinxiuensis, commonly known as the Jinxiu bubble-nest frog or Jinxiu small treefrog, is a species of shrub frog from northern Vietnam and southern China (southeastern Yunnan, northeastern Guangxi and southern Hunan).  "Jinxiu" in its names refers to the Jinxiu Yao Autonomous County, where its type locality lies.  This species in known from forests, montane forests, secondary growth, forest edges, and from near streams.

Lakkja language: The Lakkja language (), also spelled Lakkia, is a Tai–Kadai language spoken in Jinxiu Yao Autonomous County, Laibin, east-central Guangxi, China.  Lakkja people are also known as the "Chashan Yao", or Tea Mountain Yao, since they were traditionally considered by neighboring peoples to be a Miao–Yao (Hmong–Mien) people.  The name "Lakkja" means "mountain people".  All Lakkja dialects have 5 tones.

G8011 Kaiyuan–Hekou Expressway: The Kaiyuan–Hekou Expressway (), commonly referred to as the "Kaihe Expressway" () is an expressway that connects Kaiyuan, Honghe Hani and Yi Autonomous Prefecture, Yunnan, China and Hekou Yao Autonomous County, Honghe Hani and Yi Autonomous Prefecture, Yunnan.  It is a spur of G80 Guangzhou–Kunming Expressway and is entirely in Yunnan Province.

Lào Cai: Lào Cai (  ) is a city in the Northwest region of Vietnam.  It is the capital of Lào Cai Province.  The city borders the city of Hekou Yao Autonomous County, in the Yunnan province of southwest China.  It lies at the junction of the Red River (Sông Hồng) and the Nanxi River (Yunnan) approximately 160 miles (260 km) northwest of Hanoi.

Hekou Yao Autonomous County: The Hekou Yao Autonomous County () is an autonomous county in the southern part of the Yunnan province of China.  It is part of the Honghe Hani and Yi Autonomous Prefecture and borders the northern Vietnamese town of Lào Cai.  It was apparently known as Zhongcheng () during the Tang dynasty.

Du'an Yao Autonomous County: Du'an Yao Autonomous County (zhuang: Duhnganh Yauzcuz Swci Yen ,) is an autonomous county under the administration of Hechi City, in the northwest of Guangxi, China.  It has an area of 4095 km2 and a population of 625,100, including 596,100 that are of minority ethnic groups.

Supporting paragraphs: Hekou Yao Autonomous County Lhasa (prefecture-level city)
Answer: It is part of the Honghe Hani and Yi Autonomous Prefecture and borders the northern Vietnamese town of Lào Cai.