Sir i am stuck for this Question

Q11.3 20 Points Danica has 15 indistinguishable bagels that she wants to distribute among 5 people. Some people might receive zero bagels, it's possible that one person receives all of the bagels. Danica will distribute all of the bagels among these 5 people. (a) How many ways are there for Danica to distribute the bagels? Fully justify your answer. (b) How many ways are there for Danica to distribute the bagels, subject to the additional constraint that each person receives at least one bagel