题目

Not exactly, but Dr. Joseph Bell, the man who inspired the character of Sherlock Holmes, shared many qualities with the famous detective. Arthur Conan Doyle, the writer and creator of Holmes, met Dr. Bell in 1877 at the University of Edinburgh Medical School. Conan Doyle was studying to be a doctor and Bell was one of his professor.Bell was 39 years old when Conan Doyle first attended one of his lectures. He is said to have walked with great energy. His nose and chin were angular and his eyes twinkled with intelligent humor. Bell, who was a brilliant doctor, liked writing poetry, playing sport如图，点A，B，C，D为⊙O上的四个点，AC交BD于点E，∠DAC=∠BDC，CE=4，CD=6，则AE的长为（　　） A、4B、5C、6D、7