Using the notation studied on the book we have these values

Using the notation studied on the book, we have these values in the Pipeline Registers: EX/MEM.RegisterRd = ID/EX.RegisterRs = $zero (address of the zero register) Do we have a Data Hazard? No Yes

Solution

When Pipeline Registers: EX/MEM.RegisterRd = ID/EX.RegisterRs = $zero then there will be no data hazard

because when EX/MEM.RegisterRd 0, MEM/WB.RegisterRd 0 then oly data hazard occours.

so in the above probllem there is no data hazard.