Explanation:

In a tree data structure, the individual elements are known as nodes. The correct answer is option 'B' - nodes.

Nodes in a Tree:
- A tree is a hierarchical data structure that consists of nodes connected by edges.
- Each node in a tree can have zero or more child nodes.
- The nodes in a tree represent the elements of the data structure.

Characteristics of Nodes:
- Each node in a tree can have multiple children but only one parent (except for the root node, which has no parent).
- The nodes in a tree can be organized in a hierarchical manner, with one node being the parent of another node.
- The nodes in a tree are connected by edges, which represent the relationships between the nodes.

Vertices, Points, and Edges:
- While vertices, points, and edges are terminologies used in graph theory, they are not commonly used in the context of trees.
- In graph theory, vertices and nodes are often used interchangeably to refer to the elements of a graph.
- Points and edges are used to describe the connections between the vertices in a graph.

Conclusion:
- In the context of a tree data structure, the elements are called nodes.
- The nodes represent the individual elements of the tree, and they are connected by edges to form a hierarchical structure.
- Therefore, the correct answer is option 'B' - nodes.