Confused about what plant or plants to observe

I don't understand if I should only observe one sunflower, or all of them. I have 8 plants fairly close together, so it's easy for me to observe them at the same time. However, the data sheet asks for "# open flowers on your plant" implying that I should only observe one plant. What should I do? Just pick one plant? If so, and a bee visits a neighboring plant, do I count it or not?