Which of the following is considered the most accurate and precise oxygen delivery system available for clinical use?

A 58-year-old man presents with irritability progressing to confusion and altered sensorium over 2 days. He has a known history of chronic liver disease along with mild renal impairment. His blood glucose level is normal. Which clinical feature MOST strongly supports a diagnosis of hepatic encephalopathy?

Given below are two statements: Assertion (A): Progression from confusion to coma in hepatic encephalopathy is usually sudden without preceding behavioral changes. Reason (R): Metabolic encephalopathies often show a stepwise progressive deterioration of cortical function. In light of the above statements, choose the correct option: