The … results proved that the patient had hepatitis.

Analyze the question: We need a word that fits before "results" and makes sense in a medical setting: results that proved a patient had hepatitis.

Explain the concept: This is a vocabulary-in-context question. The word before "results" works as a modifier (a noun adjunct), so we need a noun that naturally combines with "results" and refers to a medical procedure that produces results.

Check each option:

• A. investigation results: An investigation is a broad, formal inquiry (e.g., police or committee). "Investigation results" is possible but unnatural for a medical lab finding.
• B. diagnosis results: A diagnosis is the conclusion that a patient has a disease. Results don't come from a diagnosis; a diagnosis comes from results. So this is illogical.
• C. probe results: A probe is a physical instrument or a deep inquiry. It is not the usual word for medical lab outcomes.
• D. test results: A test (such as a blood or laboratory test) produces results, and "test results" is the standard collocation. Results from a test can prove that a patient has hepatitis.

Answer: The sentence reads: "The test results proved that the patient had hepatitis."

Tip: In "completes the sentence" questions, ask whether the word is the cause/process or the conclusion. Tests produce results, and results lead to a diagnosis, so "diagnosis results" is backwards. Also learn common collocations such as test results, exam results, and laboratory results.