A Study to Evaluate the Safety and Efficacy of Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir With or Without Ribavirin in US Veterans With Genotype 1 Chronic Hepatitis C Virus Infection

* US military veteran currently receiving healthcare through the Veterans Health Administration * Screening laboratory result indicating hepatitis C virus (HCV), genotype 1-infection * Positive for hepatitis C antibodies or HCV RNA at least 6 months before Screening, and HCV RNA \> 1,000 IU/mL at the time of Screening or HCV RNA \> 1,000 IU/mL at the time of Screening with a liver biopsy consistent with chronic HCV-infection (or a liver biopsy performed prior to enrollment with evidence of chronic hepatitis C disease)

* Women who are pregnant or breastfeeding * Positive test result for hepatitis B surface antigen (HbsAg) or anti-HIV antibodies (HIV Ab) * Prior or current use of any investigational or commercially available anti-HCV agents other than IFN, pegIFN, RBV or sofosbuvir * Any current or past clinical evidence of Child-Pugh B or C classification * Confirmed presence of hepatocellular carcinoma indicated on imaging techniques within 3 months prior to Screening or on an ultrasound performed at Screening for participants with cirrhosis