Define a function f(x)= array l x, if x is irrational x, if x is rational. array . Then f(x) is

Options

1. Anot continuous at any point of the interval (- , ) .
2. Bcontinuous at some point(s), but not differentiable at any point of the interval (- , ) .
3. Ccontinuous at some point(s) of the interval (- , ) , but not differentiable at some of these point(s).
4. Dcontinuous at some point(s) of the interval (- , ) and differentiable at all these point(s).