Information:  - Cambodia (or Kampuchea ), officially known as the Kingdom of Cambodia (Preh Réachéanachâk Kâmpchéa), is a country located in the southern portion of the Indochina Peninsula in Southeast Asia. It is in area, bordered by Thailand to the northwest, Laos to the northeast, Vietnam to the east, and the Gulf of Thailand to the southwest.  - Sourigna Vongsa ( ) was the king of Lan Xang and during his period, it considered the golden age of Laos. He ascended to the throne in 1637.  - Stung Treng is the capital of Stung Treng Province, Cambodia. It is located in the western part of the Virachey National Park. It is the major city (and capital) of both the district and province and has a population of 29,665 (2009). In Lao, the city's name is known as "Xieng Teng".  - Attapeu, also written as Attopu or Attapu, is the capital of Attapeu Province, Laos. It is the southernmost among provincial capitals in Laos opposite Phongsali in the north.  - The term Champa refers to a collection of independent Cham polities that extended across the coast of what is today central and southern Vietnam from approximately the 2nd century through 19th century (1832), before being absorbed and annexed by the Vietnamese state. The kingdom was known variously as "nagara Campa" (Sanskrit:  ) in the Chamic and Cambodian inscriptions, in Vietnamese ("Chiêm Thành" in Sino-Vietnamese vocabulary) and (Zhànchéng) in Chinese records.  - Kham Nai was king of the southern Laotian Kingdom of Champasak from 1856 - 1858 .  - The Kingdom of Champasak (Lao:  [càmpàsák]) or Bassac, (17131946) was in 1713 proclaimed a Lao kingdom under Nokasad, a grandson of King Sourigna Vongsa, the last king of Lan Xang; and son-in-law of the Cambodian King Chey Chettha IV. Bassac and the neighboring principalities of Attapeu and Stung Treng, emerged as power centers under what was later to be described as the Mandala Southeast Asian political model.    After reading the paragraphs above, choose the best answer for the entity that related to 'kham nai' with the relationship of 'country of citizenship'.  Choices: - cambodia  - laos  - thailand  - vietnam
The answer to this question is:
laos