21.Which sequence corresponds to a BFS on the following graph, starting from vertex 7? a. 7, 1, 2, 9, 0, 4, 5, 6, 8,.3 b. 7, 9, 1, 2, 6, 0, 5, 8,4, 3 c. 7, 2,1, 9, 6, 5, 4, 8. 3, C0 d. 7,1, 2, 9, 8, 4, 0, 6, 3, 5 2 6 22.Which sequence does NOT correspond to a DFS on the following graph, starting from vertex 3? a. 3, 6, 4, 8, 5, 7, 9, 0, 2,'1 b. 3, 6,4, 9, 0, 2, 8, 1, 5, 7 c. 3, 2, 4, 6,8,1, 5, 7,9,0 d. 3, 2, 0, 9,4,6, 8, 7, 5,'1 6 23. Which vertices, if individually removed, would cause the following graph to no longer be biconnected? Choose all that apply d. 3 g. 6 h. 7 9 2