The following code is executed on the five$-$stage pipelined MIPS we studied in class. lw $$1,40($$$6)$ add $$2,$ $$3,$ $$1$ add $$1,$ $$6,$ $$4$ sw $$2,20($$$4)$ and $$1,$ $$1,$ $$4($a$)$ Assume that there are no forwarding and no hazard detection $($no stalling mechanism$).$ Insert nops to ensure correct execution. $($b$)$ Assume no forwarding and no hazard detection as in $($a$).$ Use nops only when a hazard cannot be avoided by rearranging these instructions. Use register R$7$ to hold temporary values in your modified code, if necessary. $($c$)$ If the processor has forwarding, but we forgot to implement the hazard detection unit, what occurs when this unmodified code executes?