question_answer

If function \[f(x)=\left\{ \begin{matrix}    x\,\,\,\,\,, & \text{if}\,x\,\text{is rational}  \\    1-x, & \text{if}\,x\,\text{is irrational}  \\ \end{matrix}, \right.\] then \[f(x)\] is continuous at ...... number of points [UPSEAT 2002]

A)            \[\infty \]

B)            1

C)            0

D)            None of these