4. When silicon chips are fabricated, defects in materials (e.g., silicon) and manufacturing errors can result in defective circuits. A very common defect is for one signal wire to get broken and always register a logical 0. This is often called a "stuck-at-0" fault. (a) Which instructions fail to operate correctly if the MemToReg wire is stuck at 0? (b) Which instructions fail to operate correctly if the ALUSrc wire is stuck at 0? (c) Which instructions fail to operate correctly if the Reg2Loc wire is stuck at 0