Classic label says it will control sunflowers. However, since you have already applied Pursuit, I would be cautious about applying Classic overtop of using Pursuit.  As I recall from years gone by, that was something that wasn't to be done.  I think the concern is carryover onto the next crop.  If you are going to go back to beans next year, you might be okay.

Basagran label says it controls wild sunflowers. I suggest getting a Basagran label and checking it out - see if you think it will work for you.

I would expect Cobra would control sunflowers. (I did not check the label.)  You should know what to expect if you have never used Cobra before.

edit: I checked the Cobra label. Cobra label says wild sunflowers up to 2-leaf stage.  Basagran should be able to do better than that, and it would be safer to use as well.