The accurate statement about modern Buddhism among the options provided is:
"More than two million Buddhists live in the United States."
This statement is correct, as estimates suggest that the number of Buddhists in the U.S. is indeed over two million, although exact figures can vary. The other statements are inaccurate, as Buddhism is not widely practiced in its country of origin, India, in comparison to other countries; millions of Buddhists live in Asia; and most Buddhists do not live in monasteries.