The graph represented by the following adjacency matrix is:

$\left[\begin{array}{ccccc}0& 1& 1& 1& 0\\ 1& 0& 0& 0& 1\\ 1& 0& 0& 0& 1\\ 1& 0& 0& 0& 1\\ 0& 1& 1& 1& 0\end{array}\right]$

Select one:

a$.$

b$.$

c$.$

d$.$ NOTA