Before backfill can be done you need to do what first?

Put on the sill plate
Water proof the inside of the wall
Or Block bracing

Water proof the outside of the wall. Unless you are taking a test from over 70 years ago...

Ok thanks for you help. I'm studying for the residential builders exam and I couldn't find that answer for the homework anywhere. In the question it says inside of the wall. But as long as that's the answer that all I need to know . Thanks again

No no I was just being sarcastic! I would guess they want block bracing. Unless the top row of blocks is open, and dirt would get in without the sill. Nobody builds block foundations anymore, do they?

A sill plate does offer some support. However, a comment such as "backfill" would suggest below grade. Most below grade block foundations would have some type of pilaster, typically at intersection and middle wall length.
https://tse1.mm.bing.net/th?id=OIP.gK8JYojwKAfb3Yk5r5kfbgEsDR&w=156&h=105&c=8&rs=1&qlt=90&dpr=1.25&pid=3.1&rm=2 (https://www.bing.com/images/search?q=block+pilaster+design&id=5356B9FD9786F923F6A828AF0F8CCAD2305449B5&FORM=IQFRBA)Block is rarely used below grade due to porosity, even with coatings.