4) Consider a Mealy machine based sequential circuit having one input X and one output Z. The output Z will be 0 except the input sequence 1101 are the last 4 inputs received on X. a) Determine the states and draw the state diagram. b) Encode your states for using minimal number of flip-flops. c) You will use D-type flip-flops. Obtain the state transition table. d) Derive the minimal sum-of-product (SOP) Boolean expressions for next states and the output in terms of the input and current states. e) Draw the circuit with D-type flip-flops and AND, OR and NOT gates.