Which of the following led to conflict between great britain and china in the mid 19th century

The answer is Opium War that was fought between China and Great Britain. This was due to the growing problem caused by the Opium trade by the British. This alarmed the Chinese and destroyed some of the opium being sold by the British. This led to war and China was defeated. The Treaty of Nanking where the British acquired businesses from China without any commitments.