When I click restore backup in WHM I am presented with: Daily, Weekly and Monthly buttons. If I click one of those buttons will it restore every single site or can I choose a site to backup?

You will choose which one first.

Under the backup menu in WHM, there should be 2 options:

Restore Backups
Restore Multiple Backups

If you select "Restore Backups" you can select a single account to restore.

Thanks guys, didn't want to take the chance of choosing one and then all the sites being restored to an older date. I assumed they would let you choose a site, it only made sense.

Thanks again.