阅读下面短文，根据短文内容，从A,B,C三个选项中选出可以填入空白处的正确答案。
A
A famous symbol in American culture is a cartoon animal—Mickey Mouse. Mickey first 1 in a cartoon in New York in 1928. Walt Disney was the father of Mickey. He made lots of cartoons with Mickey. Many people around the world love the mouse with two 2 ears. He was so popular because he was like a common man, but he always tried to face any danger and solve the problems all by himself. In Disney's early films, Mickey was 3,he lost his house and girlfriend, Minnie. 4,he never gave up his efforts and always won at last. Most people want to be like him. Now Mickey Mouse is still one of the most popular 5 characters in the world.
CACBA
轴的非负半轴为角的始边，如果角
、
的终边分别与单位圆交于点
和
，那么
等于
