Use Warshall's algorithm to compute the transitive closure of the graph with the following adjacency matrix: 0 |1 0 0 [Select ] 0 |1 0 Choose the correct values for the unknown variables after each of the four steps for the algorithm. After the first step: C1 After the second step: 0 1 0 0 0 0 1 C2 0 a1 0 1 O 1 0 0 1 a2 0 1 1 b 0 1 1 1 0 0 1 b2 0 1 1 1 O 0 1 1 0 1 [Select] After the third step: [Select] 0 1 0 [Select] C3 After the fourth and final step: | 1 1 O 0 C4 0 1 1 a4 0 1 1 b3 0 1 1 b4 O 1 1 1 0 1 1 1 O 1