نمودار شکل زیر بیانگر کدام تابع است؟

$\left\{ \begin{matrix} y=x\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\ge 0 \\ y={{x}^{2}}\,\,\,\,\,\,\,\,\,\,\,\,\,x\lt 0 \\\end{matrix} \right.$
2 )
$\left\{ \begin{matrix} y=x\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\ge 1 \\ y={{x}^{2}}\,\,\,\,\,\,\,\,\,\,\,\,\,x\lt 0 \\\end{matrix} \right.$
3 )
$\left\{ \begin{matrix} y=x\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\lt 0 \\ y={{x}^{2}}\,\,\,\,\,\,\,\,\,\,\,\,\,x\gt 0 \\\end{matrix} \right.$
4 )
$\left\{ \begin{matrix} y={{x}^{2}}\,\,\,\,\,\,\,\,\,\,\,\,\,\,x\ge 0 \\ y=x\,\,\,\,\,\,\,\,\,\,\,\,\,x\lt 0 \\\end{matrix} \right.$