题目

A 14-year-old girl was attacked by a grey bear while competing in a bike race. She managed to whisper the word bear to her rescuer. The girl suffered serious head, neck and leg wounds. Now she is in a dangerous condition in hospital. The girl was taking part in a 24-hour race through Bicentennial Park in Alaska when she was attacked by the bear. Bicentennial Park is next to Chugach State Park where some wild animals live.     The animal attacked the girl in a heavily wooded area at about 1:30 am. The girl called emergency services but she was unable to say any word. Another rider Pe下列命题：  ①1≤2；   ②2≤2；   ③2≤1；  ④实数的平方和不小于0，其中真命题的个数是A.1B.2C.3D.4