(a) Two tour guides are leading six tourists. The guides decide to split up. Each tourist must choose one of the guides, but with the stipulation that each guide must take at least one tourist. How many different groupings of guides and tourists are possible?(b) Repeat (a) but in the case in which three tour guides are leading the 12 tourists.(c) Repeat (a) but in the case in which four tour guides are leading the 12 tourists.