A box contains 2n chocolates that are of two different kinds: n of them are filled with butterscotch (B) and the other n with raspberry (R). Chocolates are drawn one by one at random without replacement until only one kind of chocolate is left in the box. Let D be the number of draws. For example, if n = 3, one possible sequence is BBRB with D = 4. If n = 4, the sequence could be BRBRRBR with D = 7. a) For n > 0, what are the possible values of D? b) Find the distribution of D. Please don't leave ambiguities like "..." or "and so on\" in your answer. Write a precise mathematical formula or provide (with justification) the name and parameters of one of the famous distributions