Is this question even complete? How many ways are there to divide a red bracelet, a yellow bracelet, a green bracelet, and a black bracelet among 4 people if each person can receive any number of bracelets, including ? Each bracelet must be given to someone. Including what?
A quick search gives web2.0calc link to the same question. Look at part (b). The full question is, "How many ways are there to divide a red bracelet, a yellow bracelet, a green bracelet, and a black bracelet among 4 people if each person can receive any number of bracelets, including 0? Each bracelet must be given to someone."
CPhill correctly answered the question by using distinguishability, where it is \(n^k\) with duplicates and \(k^n\) without duplicates. This does require duplicates, CPhill is correct.