"Refugees and asylum seekers comprise another separate category. The U.S. takes in thousands of refugees each year; from the mid-1970s through the late 1990s, for example, more than 1.1 million Southeast Asian refugees legally entered the country. In the early 2000s the U.S. had an annual limit of 70,000 on refugees and asylum seekers." In this passage, asylum means
A. an institution for the mentally ill.
b. an illness requiring health care.
C. a need for economic opportunity.
D. a place of safety, especially from persecution.