Design a counter which counts in the sequence: (20 points) 0000, 1001, 1000, 0111, 0110, 0101, 0100, 0011, 0010, 0001, 0000,
a. Use D flip-flops.
b. Use J-K flip-flops.
c. Use S-R flip-flops.
d. Use T flip-flops.
e. Draw a complete state diagram for the counter of (b) showing what happens when the counter is started in each of the unused states.