Immigration currently accounts for about of u. s. population growth.
a. one-half
b. a quarter
c. one-third
d. three-quarters

Base on the question where as ask to complete the sentence and choose among the following choices that could support the said passage and base on my understanding and research about the said topic, my answer would be letter A. One - half of U.S. population growth. I hope this would help 

B. one third. 

Per Census Bureau statistics, our estimated total US citizen population is already around 309 million people. Approximately, there are 11.8 million legal immigrants in this country. There is approximately 2.4 million illegal known immigrants (expired visas, passports, ect) and approximately 9.4 million illegal immigrants unknown, living in the US. With the total US population at approximately 309 million and the current illegal known and unknown immigrant population is at 10.8 million, I would estimate it at actually 1 third of the total population of the US. The reason being, the total legal immigrant population in the US fluctuates with the different types of immigrants. There are tourists, temporary, seasonal, and work only visas included in the criteria along with Permanent Resident immigrants. The average is a revolving 500,000 each year, sometimes less, sometimes more.

The answer is it can create volcanoes .