JEE Math Practice Question

Let ƒ : [–1,3] $$ \to $$ R be defined as $$f(x) = \left\{ {\begin{matrix} {\left| x \right| + \left[ x \right]} & , & { - 1 \le x < 1} \\ {x + \left| x \right|} & , & {1 \le x < 2} \\ {x + \left[ x \right]} & , & {2 \le x \le 3} \\ \end{matrix} } \right.$$ where [t] denotes the greatest integer less than or equal to t. Then, ƒ is discontinuous at:

1. A.only three points
2. B.four or more points
3. C.only two points
4. D.only one point