Given the question: I'm taking a test and have to guess the right answer to the question after the article. Article: Animal experts in Croatia say a bear has learned how to trick people to let him in by knocking at the door. They believe the 220- kilogram brown bear probably learned the trick while nudging a door to get it to open. Experts have a guess that the nudging was mistaken by the owners for knocking and that the bear, pleased by the result, repeated the trick. The Loknar family from Gerovo in western Croatia said the bear had knocked at their door three times and they were now refusing to answer the door. ''We jumped out of the window as he came in through the door and went into the kitchen to take some food for the first time." Mum Nevenka Loknar told a reporter from a local newspaper. "I opened the door and saw him standing there and I didn't believe my eyes at first, then I ran for it as he walked in as if _ was the most normal- thing in the world." Bears are a common thing in the woods around here, but no one has ever heard of a bear that knocks at the door. Mum Nevenka Loknar said, "The bear is so intelligent. It's incredible. We've tried to put up lots of obstacles to stop him coming in, like a wire fence but he still gets through. I wouldn't be surprised if he knew how to use wire cutters." Question: Mum Nevenka Loknar was surprised that the bear _ . Options: A: didn't attack her family B: knew how to use wire cutters C: jumped across her wire fence three times D: was clever at getting through the obstacles
The answer is:
D