Unique Genre Combination Selection

A bookstore has a special promotion where customers can select books to form a unique set. The store has a selection of 5 different genres: Mystery, Science Fiction, Fantasy, Biography, and Romance. If a customer wants to choose a set consisting of exactly 3 different genres, how many unique sets can they create? Remember that the order in which the genres are selected does not matter.

Use the combination formula, which is defined as:

$$ C(n, k) = \f\frac{n!}{k!(n-k)!} $$

where $$ n $$ is the total number of genres, and $$ k $$ is the number of genres to be selected.