Consider the following MIPS code. ADD R5, R2, R1 LW R3, 4(R5) LW R2, 0(R2) OR R3, R5, R3 SW R3, 0(R5) (a) If there is no forwarding or hazard detection, insert nopsto ensure correct execution. (b) Repeat (a) but now use nops only when a hazard cannot be avoided by rearranging these instructions. (c) If the processor has forwarding, but we forgot to implement the hazard detection unit, what happens when this code executes? (d) If there is forwarding, for the first five cycles during the execution of this code, specify which signals are asserted in each cycle by hazard detection and forwarding units in Figure 4.60