$(5$pt$)$ Flip$-$Flop design

A$.$ Draw the diagram for a D flip$-$flop with $D$ latch and $SR$ latch. $(1$pt$)$

B$.$ Draw the diagram for an $4-$bit register using $D$ flip$-$flips. The input should be $I_{3\text{:}0},$ and there must only be one input $C.(1$pt$)$

C$.$ Extend the above $4-$bit register with clear function. Do not modify your D flip$-$flop design, you must use additional gates on your design in B$.(1\mathrm{.}5$pt$)$

D$.$ Extend the above design with enabler function. Do not modify your $D$ flip$-$flop design, you must use additional gates on your design in $C.(1\mathrm{.}5$pt$)$