The solution is a and b, why is that? Thank you!

Problem 8.8 (S) Recall that in the Kosaraju algorithm, the first pass of depth-first search operates on the reversed version of the input graph and the second on the original input graph. Which of the following statements are true? (Choose all that apply.) a) The algorithm would remain correct if in the first pass it assigned vertex positions in increasing (rather than decreasing) order and in the second pass considered the vertices in decreasing (rather than increasing) order of vertex position. b) The algorithm would remain correct if it used the original input graph in its first pass and the reversed graph in its second pass. c) The algorithm would remain correct if it used the original input graph in both passes, provided in the first pass it assigned vertex positions in increasing (rather than decreasing) order. d) The algorithm would remain correct if it used the original input graph in both passes, provided in the second pass it considered the vertices in decreasing (rather than increasing) order of vertex position. Problem 8.8 (S) Recall that in the Kosaraju algorithm, the first pass of depth-first search operates on the reversed version of the input graph and the second on the original input graph. Which of the following statements are true? (Choose all that apply.) a) The algorithm would remain correct if in the first pass it assigned vertex positions in increasing (rather than decreasing) order and in the second pass considered the vertices in decreasing (rather than increasing) order of vertex position. b) The algorithm would remain correct if it used the original input graph in its first pass and the reversed graph in its second pass. c) The algorithm would remain correct if it used the original input graph in both passes, provided in the first pass it assigned vertex positions in increasing (rather than decreasing) order. d) The algorithm would remain correct if it used the original input graph in both passes, provided in the second pass it considered the vertices in decreasing (rather than increasing) order of vertex position