A widget factory has four loading docks for storing crates of ready-to-ship widgets. Suppose the factory produces 8 indistinguishable crates of widgets and sends each crate to one of the four loading docks.

a. How many ways are there to distribute the crates among the loading docks?
b. Now, assume that any time a loading dock contains at least 5 crates, a truck picks up 5 crates from that dock and ships them away. (e. g., if 6 crates are sent to a loading dock, the truck removes 5, leaving 1 leftover crate still in the dock). We will now consider two configurations to be identical if, for every loading dock, the two confirgurations have the same number of leftover crates in that dock. How would your answer in the previous part compare to the number of outcomes given the new setup? Justify your answer.
c. We will now attempt to count the number of configurations of crates. First, we look at the case where crates are removed from the dock. How many ways are there to distribute the crates such that some crate gets removed from the dock?
d. How many ways are there to distribute the crates such that no crates are removed from the dock; i. e. no dock receives at least 5 crates?