a) Draw the pipeline execution diagram (similar to the diagram in slide 78 of the MIPS Microarchitecture lecture) of the following MIPS program. lw $s1, #4 ($s3) sub $t2, $s1, $t2 SW $t4, #4 ($s3) add $s3, $t2, $t2 b) Explain, with the support of arrows on the diagram, what kind of hazards are there and why? c) Explain, with the support of arrows on the diagram, whether Data Forwarding can be used to solve the above hazards. d) Assume that there is no hardware support for hazard handling. Rewrite the above code by inserting nops instructions to avoid the above hazards.