which opk is positive???

Al
so I started taking opks the day after my period ended. These are all of them. I believe 3/31 is when I ovulated because when I took the two tests that day, they were pretty much as dark as the control line. Now that they are all dry and I'm comparing them I just dont knpw what to think. Do my two tests that I took on 3/31 look positive compared to the rest?!!