12) A directed graph G has 5 vertices, numbered 1 through 5 . The 55 matrix A is the adjacency matrix for G. The matrices A2 and A3 are given below. A2=0001000000100110100000101 A3=0010000010001011001001001 Which edge is not in the transitive closure of G ? a. (1,3) b. (2,4) c. (4,5) d. (5,5) 13) A directed graph G has 5 vertices, numbered 1 through 5 . The 55 matrix A is the adjacency matrix for G. The matrix A2 is given below. A2=0001000000100110100000101 Which vertex can be reached by a walk of length 4 that starts at vertex 1 ? a. 2 b. 3 c. 4 d. 5