All these things are related to DFS & BFS and question is based on space complexity of those.
Answer :-
BFS → O(bd) worst case space complexity
DFS → O(bm) worst case space complexity
Depth - Limited Search → O(bl)
Iterative deepening Search → O(bd)
Some point which help you ------
Branching factor - The average number of children of the nodes in the space.
Solution depth - The length of the shortest path from the initial node to a goal node.
Maximum depth - The maximum number of nodes along the longest path from the root node down to the farthest leaf node
Depth limit - The unbounded tree problem appeared in DFS can be fixed by imposing a limit on the depth that DFS can reach, this limit we will call depth limit.