Answer D
A: True , Might save a lot of memory if the graph is sparse.
B: True, In order to delete a vertex in adjacency list, we need to search for the vertex which will require O(|V|) time in worst case, after this we need to traverse the edges and in worst case it will require O(|E|) time.Hence, total time complexity is O(|V|+|E|) whereas removing a vertex in adjacency matrix will require O(V$^{2}$)
C : True , There are two pointers in adjacency list first points to the front node and the other points to the rear node.Thus insertion of a vertex can be done directly in O(1) time whereas in matrix it will require O(V$^{2}$)