Q$2.($a$)$ Design a three$-$bit binary ripple count$-$down counter using D flip$-$flops. Show the logic diagram, draw the output waveforms and briefly explain how this circuit can be used as a frequency divider. $60\%($b$)$ Briefly explain what causes static hazards in digital circuits. Implement the below Boolean function without static$-1$ hazards, using a minimum number of gates: F $($A$,$ B$,$ C$,$ D$)=$ AB$($D$+$CD$)+$ A$($B$+$CD$)+$ A$$CD$$