(6 points) A local gas station accepts payment in the form of cash, credit, debit, and check. Suppose there is a 40% chance that customers use credit, 30% chance they use debit, 20% chance they use cash, and 10% chance they use check. There are currently 20 customers getting gas, all independent from each other. Calculate the following probabilities. (a) Exactly 8 of the customers will pay using credit. (b) Exactly 8 will pay using credit and exactly 6 using debit. (c) Exactly 8 will pay using credit, 6 using debit, and 4 using cash. (Note this implies 2 will use check)