阅读下列短文，从每题所给的四个选项 （A 、B 、C  和 D ）中，选出最佳选项。

    George Bernard Shaw，the greatest and funniest British dramatist(剧作家)of the first half of the 20th century，was born in Dublin，Ireland，on July 26,1856.His early life was not happy. His father was a selfish man who drank too much and could not support his family properly. His mother was a disappointed，unhappy woman who found more pleasure in studying music than in her children. Bernard and his two sisters received little love and attention from their mother while they were young. At the age of ten Shaw entered school. At first he was the best student，but soon he was at or near the bottom of his class.

    Although he did not like school，Bernard was a good，bright，curious student. His lifelong interest in everything from music and art to machines and medicine began from school life. The interests of this tireless schoolboy were literature and music. He often entertained(使快乐)his classmates with stories he read.

    Early at the age of fifteen，he went to work in an office. He did well as an office clerk，but after five years he decided that he wanted to be a writer. He left Ireland and went to London，where he began to write seriously. Seventy-four years later the great dramatist died.

已知双曲线$\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$（a＞0，b＞0）的两条渐近线均和圆C：x²+y²﹣6x+5=0相切，则该双曲线离心率等于（　　）