For the function $f(x) = \begin{cases} -x, & x<0 \\ x^2, & x \geq 0 \end{cases}$ the $\text{CORRECT}$ statement(s) is/are
1. $f(x)$ is continuous at $x=1$
2. $f(x)$ is differentiable at $x=1$
3. $f(x)$ is continuous at $x=0$
4. $f(x)$  is differentiable at $x=0$