Kristina Karganova invites 15 relatives to a party: her mother, 3 aunts, 3 uncles, 4 brothers, 1 male cousin, and e 3 female cousins. If the chances of any one guest arriving first are equally likely, find the probabilities that the first guest to arrive is as follows.

(a) A brother or an uncle

(b) A brother or a cousin

(c) A brother or her mother