单项选择题

设函数,且f(x)无间断点,则a等于(    ).
   (A)0    (B)1    (C)e-1    (D)∞

A.174.24.96:6088/Latex/latex.action?latex=Zih4KT1cbGVmdFx7XGJlZ2lue2FycmF5fXtjY30yXnstXGZyYWN7MX17fHh8fX0sICZ4XG5lcSAw%0D%0AIFxcYSwgJiB4PTBcZW5ke2FycmF5fQ%3D%3D'
B.