Which statement correctly describes the mechanism and management of hepatic encephalopathy?

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Hepatic encephalopathy arises when the liver can't clear gut-derived toxins, especially ammonia, so toxins reach the brain due to portosystemic shunting and reduced hepatic clearance in cirrhosis. Ammonia that reaches the brain disrupts astrocyte function and neurotransmission, leading to cognitive and motor changes typical of HE. Treatment aims to lower ammonia load and remove triggers: use Lactulose, which acidifies the gut to convert ammonia (NH3) to ammonium (NH4+) and speeds its excretion, and add rifaximin, a nonabsorbable antibiotic that reduces ammonia-producing bacteria in the gut. It's also essential to identify and treat precipitating factors such as infections, GI bleeding, electrolyte disturbances, constipation, or sedative use. This combination—mechanism centered on impaired hepatic clearance with portosystemic shunting, plus lactulose and rifaximin to reduce ammonia and calm precipitating factors—best describes how hepatic encephalopathy works and is managed. The other choices describe mechanisms and treatments for different liver conditions (cholestasis with hyperbilirubinemia, autoimmune hepatitis, biliary obstruction), which do not apply to HE.