Which of the following graphs is isomorphic to

Let $$G$$ be a complete undirected graph on $$6$$ vertices. If vertices of $$G$$ $$\,\,\,\,$$ are labeled, then the number of distinct cycles of length $$4$$ in $$G$$ is equal to

Let $$A$$ be the $$2 \times 2$$ matrix with elements $${a_{11}} = {a_{12}} = {a_{21}} = + 1$$ and $${a_{22}} = - 1$$. Then the eigen values of the matrix $${A^{19}}$$ are

A process executes the code
fork $$\left( {\,\,\,} \right);$$
fork $$\left( {\,\,\,} \right);$$
fork $$\left( {\,\,\,} \right);$$
The total number of child processes created is