For a fair throw of six 6-sided dice (as in the game Farkle):

(a) Find the probability of 6 of a kind.

(b) Find the probability of two different triplets.

(c) Find the probability of a four-of-a-kind and a different pair.

(d) Now suppose the six dice are each of a different color and all placed an urn. After having chosen 4

with replacement, find the probability that two or more colors are chosen.