Which statement about vietnam, laos, and cambodia is not true?
a. all three countries were affected by the vietnam war.
b. all three countries have a majority population belonging to the khmer ethnic group.
c. all three countries were once part of french indochina.
d. all three countries were under japanese control in world war ii.

b. All three countries have a majority population belonging to the Khmer ethnic group.

Explanation:

During the colonial era, French Indochina was made up of the countries like Cochin-China, Annam, Cambodia, Tonkin, Kwangchowan, and Laos. These same regions are now divided into the nations of Vietnam, Laos, and Cambodia. On the other hand, Vietnam has a population of 1.5% of people belonging to the "Khmer ethnic group", 97% in Cambodia, and 4000 people belonging to the "Khmer" ethnic group Laos. In the Vietnam War, Vietnam was allied with Cambodia and Laos.