The true statement about the origin of the American population is B. Most Americans are immigrants or descendants of immigrants.
The population of the United States is currently made up of different groups such as:
Descendants of European immigrants (75% of the population)
Asians (less than 5% of the population)
Latinos (16.5% of the population)
African Americans (13% of the population)
Native Americans (less than 5% of the population)
These population groups are the result of different immigrations to the United States. However, the first to live there are the natives. Later the European immigrants arrived and they were who greatly increased the population of the United States.
Later in the 19th and 20th centuries, immigrants arrived from other regions of the world such as Asia, South, and Central America, the Middle East, among others, who enriched the total population of the United States. However these groups do not are the majority in Untied States population.
According to the above, the correct answer is B, because it expresses the correct idea on the subject of the population of the United States, while the other options do not provide true information.