AVL Trees:
An AVL tree is a self-balancing binary search tree. It maintains the height balance property, which ensures that the height difference between the left and right subtrees of any node is at most 1.

Maximum Height of AVL Trees:
To find the maximum height of an AVL tree with n nodes, we need to consider the worst-case scenario. In an AVL tree, the maximum height is achieved when the tree is completely unbalanced, with all nodes in a single path.

Analysis:
Let's analyze the maximum height of an AVL tree with 7 nodes.

Case 1: Height = 1
If the tree has only one node, the height is 0. In this case, it is not possible to have an AVL tree with 7 nodes.

Case 2: Height = 2
If the tree has two nodes, the height is 1. In this case, it is not possible to have an AVL tree with 7 nodes.

Case 3: Height = 3
If the tree has three nodes, the height is 2. In this case, it is not possible to have an AVL tree with 7 nodes.

Case 4: Height = 4
If the tree has four nodes, the height is 3. In this case, it is not possible to have an AVL tree with 7 nodes.

Case 5: Height = 5
If the tree has five nodes, the height is 4. In this case, it is not possible to have an AVL tree with 7 nodes.

Case 6: Height = 6
If the tree has six nodes, the height is 5. In this case, it is not possible to have an AVL tree with 7 nodes.

Case 7: Height = 7
If the tree has seven nodes, the height is 6. In this case, it is possible to have an AVL tree with 7 nodes.

Conclusion:
Among all the possible heights for an AVL tree with 7 nodes, the maximum height is 6. Therefore, the correct answer is option 'B' - 3.