Draw the recursion trace for the execution of function PrintS(3, 5, U), where S is empty and U = {a, b, c}. List all the printouts of S. Algorithm Prints(k, S, U): Input: An integer k, sequence S, and set U Output: An enumeration of all k-length extensions to S using elements in U without repetitions for each e in U do Remove e from U {e is now being used} Add e to the end of S if k = 1 then Print S else Prints (k-1, S, U) Add e back to U {e is now unused} Remove e from the end of S