Step 1: Understand Heap Construction.
To build a heap, the most efficient method involves starting from the last internal node and applying the heapify operation, which takes \( O(\log n) \) time. The heapify operation is applied to each node, and since there are \( n \) nodes, the total time complexity is \( O(n \log n) \).
Step 2: Conclusion.
Thus, the correct time complexity for building a heap of \( n \) elements is \( O(n \log n) \).

