Which of the following data structures is commonly used to represent graphs?ArrayLinked ListAdjacency ListAll of the above

All of the above.

Explanation:

1. Array: In graph theory, an array can be used to store nodes of the graph. If the graph is a weighted one, a 2D array (matrix) can be used to store the weights of the edges. This is known as an adjacency matrix representation.

2. Linked List: A linked list can be used to represent adjacency lists of all vertices of the graph. Each node in the list represents the vertices that are adjacent to a vertex.

3. Adjacency List: An adjacency list is a collection of unordered lists used to represent a finite graph. Each list describes the set of neighbors of a vertex in the graph. This is one of the most common ways to represent a graph because it is very efficient in terms of storage because you only need to store the values for the edges.

So, all of the above data structures can be used to represent graphs in one way or another.