Need help with this Algorithms problem

Problem 1: Assume that you have n elements stored in a binary search tree T Show how to output the elements in sorted order, i.e. show an algorithm that takes as input T and outputs an array A containing all the elements of T in sorted order. What's the running time of your algorithm? . Consider the following problem. You are given n elements in an unordered array B and you want to put them in a binary search tree (not necessarily balanced). Use the answer of the previous question to argue that any algorithm for this task must make at least (n log n) comparisons