单选题 They are giant geometric patterns, which appear over-night in a field of crops. Many people believe that they are made by aliens. Others call them hoaxes. " Crop circle", as the mysterious patterns are called, became a hot phrase this month.
A strange pattern 360 feet (110 meters) in diameter was discovered earlier this month in a wheat field in Oxfordshire, England. It's believed to be the world's first three-dimensional crop circle. The giant crop circle gives an impression of looking down on skyscrapers from above. The design's discovery immediately generated a new tide of public interest in this mysterious phenomenon. Crop circles were first widely noticed in the late 1970s as many mysterious circles began appearing in crop fields throughout the English countryside. People were intrigued by these giant patterns. They were huge (at least tens of meters in diameters) and popped up over-night. No one knew how or by whom they were made.
The world's first three-dimensional crop circle appeared

• A. in a wheat field in Oxfordshire.
• B. throughout the countryside of Oxfordshire.
• C. in the English countryside in the 1970s.
• D. in all the wheat fields in the English countrysid