A 2019 article in JAMA: Psychiatry3 presents the results of a randomized controlled trial of Esketamine nasal spray plus oral antidepressant (Treatment group) versus a placebo nasal spray plus oral antidepressant (Control group) for preventing relapse in patients diagnosed with treatment-resistant depression. Patients in stable remission (free of depressive symptoms) were followed for up to 86 weeks after randomization, until a relapse (reoccurrence of depressive symptoms) or censoring. The risk of relapse in the follow-up period is summarized by randomization group in the following Kaplan-Meier curve. The vertical dashes on each curve represent censoring times. 3 Daley E, et al. Efficacy of Esketamine Nasal Spray Plus Oral Antidepressant Treatment for Relapse Prevention in Patients With Treatment-Resistant Depression A Randomized Clinical Trial. JAMA. 2019;76(9):893-903

Based on the Kaplan-Meier curve, approximately what proportion of patients randomized to the control group who relapsed (had the outcome) within 16 weeks of being randomized to this group? a. 82% b. 60% c. 40% d. 18%