Complete diagram here:

$($b$)$ How many clock cycles per loop iteration are lost to branch overhead?

Hint: Based on the diagram you have drawn above, compare the clock cycles when the second

LW instruction starts, under two scenarios:

If BNZ is not there, and o

If BNZ is there.

The difference between the two is the delay $($overhead$)$ due to the branch.

Note: I am unsure about my diagram, but I think the branch overhead is $4$ cycles.