If two trees have same structure and but different node content, then they are called ___a.Synonyms treesb.Joint treesc.Equivalent treesd.Similar trees

The correct answer to the question is c. Equivalent trees.

Explanation

In computer science, especially in the context of data structures, two trees are considered equivalent if they have the same structure (i.e., the arrangement of nodes and their relationships) but can contain different values at the nodes. This means that while the layout or organization of the nodes follows the same pattern, the actual content of these nodes may differ.

The options provided can be understood as follows:

1. Synonyms trees: This term is not standard in computer science.
2. Joint trees: This is also not a recognized term in the context of tree data structures.
3. Equivalent trees: This correctly identifies trees that match in structure, regardless of the data contained in them.
4. Similar trees: While this may imply some level of resemblance, it does not specifically denote that the structures are the same.

Thus, the most appropriate term that fits the definition given in the question is "Equivalent trees".