The correct answer is: A. Depth-first search algorithm.
Backward chaining is a search technique used in artificial intelligence to solve problems. It starts with a goal and works backwards to find the steps that need to be taken to achieve that goal.
Depth-first search is a search algorithm that starts at the root node of a search tree and explores all of the nodes that are reachable from the root node before exploring any other nodes.
Breadth-first search is a search algorithm that starts at the root node of a search tree and explores all of the nodes that are one level away from the root node before exploring any other nodes.
Hill-climbing is a search algorithm that starts at a random node in a search space and then moves to the neighboring node that has the highest value.
Of the three algorithms, depth-first search is the most similar to backward chaining. This is because both algorithms start with a goal and work backwards to find the steps that need to be taken to achieve that goal.
Breadth-first search and hill-climbing are not as similar to backward chaining. This is because these algorithms do not start with a goal. Instead, they start at a random node in a search space and then move to the neighboring node that has the highest value.