Apply the DFS algorithm on the undirected graph of Question $\backslash$sigma and show its traversal starting at vertex a$.$ Assume that vertex's adjacencies are considered in alphabetical order. Highlight visited vertices and explored edges with discovery edges drawn as solid lines $($ar use a highlighter$)$ and nontree$($back$)$ edges as dashed lines. Label each edge with integer numbers as $1,2,3,...$ in the order of discovery.