Heaps

Step 1: Understanding Heap Properties.
- **Parent(i)**: We can compute the parent of node using the formula , which gives the index of the parent node in a binary heap.

- **Left(i)**: We can compute the left child of node using the formula .

- **Right(i)**: We can compute the right child of node using the formula .

Step 2: Heap Size.
We cannot compute the heap size directly from the index of a node. The heap size is generally known from external information or passed along with the heap structure.

Step 3: Conclusion.
Thus, the correct answer is **(2) Heap size**.