Problems in this exercise refer to the following sequence of instructions, and assume that it is executed on a 5-stage pipelined datapath: add $s5,$s2,$s1 lw $s3,4($s5) lw $s2,0($s2) or $s3,$s5,$s3 sw $s3,0($s5) a. If there is no forwarding or hazard detection, insert NOP instructions to ensure correct execution. Rewrite the instruction sequence with NOPs inserted in your answer. b. Now use NOPs only when a hazard cannot be avoided by changing or rearranging these instructions from your answer (a).