ADP binds to platelets in order to intiate the activation process. Two binding sites were identified on platelets, one with a Kd of 350 nM and one with a Kd of 7.9 µM. Which of these is the low-affinity binding site? A) The binding site with a Kd of 350 nM is the low affinity site. B) The binding site with a Kd of 7.9 µM is the low affinity site. C) No way to tell