Suppose we perform Depth First Search (DFS) on a digraph G=(V,E) given by its adjacency list structure and label each node uV by d[u] and f[u], indicating the starting and finishing times of DFSvisit(u), as we learned in the course. Consider an arbitrary pair of distinct vertices u and v such that there is a directed path from u to v in G. Then that implies (If more than one choice is correct, select the red choice.) a. d[u]f[v]. d. More than one of the other choices are correct. e. d[u]