Answer & Explanation
Answer: Option [C]
The tightest upper bound that represents the time complexity of inserting an object into a binary search tree of n nodes O(n)
In binary search tree to insert an object we first search the object from the root and always insert at the leaf.
For an unbalanced binary search tree all the nodes are required to traverse to insert as child after the last leaf.
So the required answer is O(n)