 This study is to evaluate the safety, tolerability, and antiviral efficacy of ledipasvirsofosbuvir LDVSOF fixed-dose combination FDC with or without ribavirin RBV, administered for 8 or 12 weeks of treatment in participants with chronic genotype 1 hepatitis C virus HCV infection who are treatment-naive, and for 12 weeks in participants who had previously received a regimen containing a protease inhibitor for the treatment of HCV. 