You are to design a sequential circuit for the following electronic Vending Machine Controller (VMC). The vending machine sells only one type of chocolate bar for 20. The machine accepts N (nickels = 5) and D (dimes = 10). When the sum of the coins inserted in sequence is 20 or more, the machine dispenses one chocolate bar by making the output CD (Chocolate Dispense) equal to 1 and returns to initial state. No change is returned in case the total amount is greater than 20. CD output equals 0 for all other states. If the CR (Coin Return) pushbutton is pushed, regardless of the total amount, the deposited coins up to that point are returned through the coin return by setting the output R (Returned coins) to 1 (i.e. CR has priority over both D and N inputs), after which the machine returns to its initial state. R equals 0 in all other states. Use Moore machine for your design (Hint: Use separate states for each possible total amount). inputs N D CR Clock- Vending Machine Controller (VMC) CD R outputs a) Derive the complete state diagram, describe the meaning of each state clearly. b) Determine the number of state variables to use and assign binary codes to the states in the state diagram, c) Choose the JK FF for the implementation. Give the complete state table (in numeric order) of the VMC.