For a sequential circuit realize the following logic equations:

$Q_1^{+}=x^{\text{'}}xO{R}_2{Q}_2$

$Q_2^{+}=x^{+}{Q}_1+Q_2$

$Z=x{Q}_1{Q}_2^{\text{'}}$

a$)$ Draw the logic diagram using DFFs

b$)$ Write the next state table for this circuit

c$)$ Using the state assignments $\{A,B,C,D\}=\{00,01,11,10\},$ draw the state transition diagram corresponding to $b.$