Which of the following mainland countries of Southeast Asia was never a European colony?

A. Thailand

B. Burma (Myanmar)

C. Cambodia

D. Laos

The correct answer is Thailand: it has never been a colony ... so it also has never been a colony of an European country.

Burma was a British colony, known as British Burma, and it was a part of British India.

Cambodia and Laos were both part of French Indochina - a French colony