If 10 distinguishable balls are distributed among 4 urns in such a way that all arrangements are equally likely, what is the probability that (i) a specified urn will contain 6 balls, (ii) the first urn will contain 4 balls, the second urn will contain 3 balls, the third urn will contain 2 balls, and the fourth urn will contain J ball, (iii) all urns will be occupied?