The question in the image is asking about the correct description of Depth-First Search (DFS).

The options are: A. 是一种逐层搜索的算法 (It is a layer-by-layer search algorithm) B. 先放入OPEN表的节点先被拓展 (The nodes placed first in the OPEN list are expanded first) C. 如果问题有解，分支有界搜索一定可以找到解 (If the problem has a solution, bounded branching search will definitely find a solution) D. 迭代加深搜索相当于深度优先搜索与宽度优先搜索的结合 (Iterative deepening search is equivalent to a combination of depth-first search and breadth-first search)

The correct answer is:

D. 迭代加深搜索相当于深度优先搜索与宽度优先搜索的结合 (Iterative deepening search is equivalent to a combination of depth-first search and breadth-first search)

Depth-First Search (DFS) is indeed a search algorithm that explores as far as possible along each branch before backing up, and Iterative Deepening Depth-First Search (IDDFS) combines the benefits of both DFS and Breadth-First Search (BFS).

Would you like further details or have any questions? Here are some questions you might want to ask:

1. What are the differences between DFS and BFS?
2. How does Iterative Deepening Depth-First Search (IDDFS) work?
3. Can you provide an example of a problem where DFS is used?
4. What are the advantages of using DFS over BFS?
5. Are there any specific use cases where DFS is preferred?

Tip: When tackling algorithmic problems, understanding both the theoretical aspects and practical applications can greatly enhance your problem-solving skills.