Passage Summary: A doctor thought a patient needed more medicine. First, they tried more medicine, but it didn't work. Then they found out a tea was blocking the medicine. They tried the regular dose without the tea, and that didn't work either. Finally, they tried the high dose without the tea, and it worked, proving the high dose was indeed necessary.

Conclusion: The doctor's initial hypothesis that the dosage was insufficient was correct.

Reasoning: The medication only worked when the dosage was doubled and the interfering herbal drink was removed, whereas removing the drink alone with the original dose did not work.

Analysis: This 'Method of Reasoning' question asks how the final steps support the initial hypothesis. The doctor uses a controlled approach to rule out an alternative explanation. By testing the initial dosage without the herbal interference and seeing it fail, the doctor demonstrates that the interference wasn't the only reason the treatment failed. The final success with the doubled dose (minus the interference) confirms that the higher dosage was a necessary component of the cure. Look for an answer that describes the elimination of an alternative cause to isolate the true cause.