题目内容：
请根据下面短文回答第题： What is the mother bear doing now in March? She's sleeping.
Last autumn, after having eaten very well, she made a de~n, covering the inside with dry grass, under a tree．In the beginning of winter, she went into it．"What a fine place it is," she thought to herself, "and how nice and warm! I'll spend all winter in here．" She went to sleep at once, but she did not fall into a very deep sleep.For, in January, the mother bear has given birth to baby bears．While still half sleeping, shehas licked (舔) them clean.
Her body clock will go off in April．And then she will go out of her den to look for foodfood for herself and for her young．The babies will be a lot bigger by then.
As soon as it is warm enough, the family will leave the den and the mother bear will start teaching the baby bears the lessons of life．to catch their attention( 注意), she gives some caresses(爱抚), but when the babies do not listen to her, she will beat them．This is the way for all the bears in the world, whether in Europe, in Asia, or in America.
When does the mother bear sleep? A．From early autumn to March.
B．From early winter to March.
C．From early winter to April.
参考答案：
答案解析：