Mountain lions live in mountainous areas of the western prefix = st1 /United States. Lately, however, people have reported seeing them in quiet neighborhoods all across the country! Usually considered shy and seldom seen, these lions are becoming more noticeable. In addition, the lions appear to be moving east. They were even reported in the suburbs of Boston, Philadelphia, andChicago. It seems certain that these "Kings of the mountains" are moving. Why? Scientists are not sure. Some think that as the mountain lion population increases in the west, younger wild cats are leaving the area. These cats are searching for new homes and new places for food. "The young males are looking for new homes," says Lynn Sadler, who is the director of the Mountain Lion Foundation in Sacramento,Calif."People tend to create too many barriers, such as buildings, fences, roads, and noise. As the mountain lions seek new places and food and water sources, these barriers get in their way." The sightings  have made people increasingly watchful  . Sometimes the "mountain lions" that people report seeing turn out to be large dogs or even house cats. But at least a few of the meetings have been real. The building of new roads, the growing of suburbs and the growing popularity of outdoor activities are all increasing the chances that people in various parts of the country may meet up with a mountain lion. Because many people are concerned about the reappearance of the American lion, an expert outlined some ways they can avoid attracting the wild cats: Never leave pets or pet food outside; properly care for farm animals; and plan public land use to enable the lions to move safely from one place to another. "To be fair," says the expert, "mountain lions are trying to regain their homes. They were here first. Now we need to find ways we can live together." According to the passage, it is clear that   _  .
the reported sightings of mountain lions have not been proved people walking in the country may come across a lion fences have been built to protect the lions mountain lions prefer urban areas
Question: Mountain lions live in mountainous areas of the western prefix = st1 /United States. Lately, however, people have reported seeing them in quiet neighborhoods all across the country! Usually considered shy and seldom seen, these lions are becoming more noticeable. In addition, the lions appear to be moving east. They were even reported in the suburbs of Boston, Philadelphia, andChicago. It seems certain that these "Kings of the mountains" are moving. Why? Scientists are not sure. Some think that as the mountain lion population increases in the west, younger wild cats are leaving the area. These cats are searching for new homes and new places for food. "The young males are looking for new homes," says Lynn Sadler, who is the director of the Mountain Lion Foundation in Sacramento,Calif."People tend to create too many barriers, such as buildings, fences, roads, and noise. As the mountain lions seek new places and food and water sources, these barriers get in their way." The sightings  have made people increasingly watchful  . Sometimes the "mountain lions" that people report seeing turn out to be large dogs or even house cats. But at least a few of the meetings have been real. The building of new roads, the growing of suburbs and the growing popularity of outdoor activities are all increasing the chances that people in various parts of the country may meet up with a mountain lion. Because many people are concerned about the reappearance of the American lion, an expert outlined some ways they can avoid attracting the wild cats: Never leave pets or pet food outside; properly care for farm animals; and plan public land use to enable the lions to move safely from one place to another. "To be fair," says the expert, "mountain lions are trying to regain their homes. They were here first. Now we need to find ways we can live together." According to the passage, it is clear that   _  .
A. the reported sightings of mountain lions have not been proved
B. people walking in the country may come across a lion
C. fences have been built to protect the lions
D. mountain lions prefer urban areas
Answer: