Let

$A=\left[\begin{array}{cc}1& -2\\ 1& 0\\ 1& 1\\ 1& 3\end{array}\right],b=\left[\begin{array}{c}-4\\ -3\\ 3\\ 0\end{array}\right]$

c$)$ If widehat$(b)=0,$ which subspace of $A,$ is $b$ in$?$