Take the following as truth: To Queen Victoria, Lin addressed a famous letter, pointing out the harm the  poisonous drug  did to China, and asking for an end to the opium trade; his arguments are unanswerable, but the lofty though heartfelt tone of the letter shows how unprepared the Chinese were to negotiate with the West in realistic terms.
Then the following statement: "The introduction of drugs into China was due to tourists." is true, false, or inconclusive?
Answer: Inconclusive