The statement is accurate. Authoritative medical sources explicitly describe hepatitis C as a viral infection of the liver caused by the hepatitis C virus. While the disease can also have effects outside the liver and may become chronic, those facts do not make the core description incorrect.
Caveats
Hepatitis C is not only clinically relevant to the liver; it can also cause extrahepatic complications affecting blood vessels, kidneys, skin, and other organs.
A short definition omits that hepatitis C can be acute or chronic, with chronic infection driving much of the long-term harm such as cirrhosis and liver cancer.
Less authoritative background or commercial sources are unnecessary here because major public-health and medical references already directly support the claim.