2. Which of them represent paths represents a tree. a. vlelv2 and vle2v3e3v3 b. vlelv2e4v5 and vle2v3e3v3 c. vlelv2e4v1 and vle2v3e3v4 d. v2elv3 and v2e2v3e3v5 3. Let D be a graph on 25 edges such that there is a vertex of degree 1, a vertex of degree 2, a vertex of degree 3, a vertex of degree 4, a vertex of degree 5, a vertex of degree 6, a vertex of degree 7, a vertex of degree 8 and a vertex of degree 9. What can be the degree of the last vertex?Bottom of Form a) 4 b) 2 c) 0 d) 5 4. What would be the number of zeros in the adjacency matrix of the given graph? a) 4 b) 12 c) 16 d) 8 3.Evaluate the postfix expressions a. 20 2 8 * +9/3- b. Draw the binary search tree for the expression 20 2 8 * + 9/3