The combination coefficient n−1Cm denotes -
(a) The number of ways in which n things of which m are alike and rest different can arrange in a circle.
(b) The number of ways in which m different things can be selected out of n different thing if a particular thing is always excluded.
(c) Number of ways in which n different balls can be distributed in m different boxes so that no box remains empty and each box can hold any number of balls.