Which of the following methods is associated with the manufacture of controlled substances?

The method associated with the manufacture of controlled substances is chemical synthesis or extraction methods. This is because the production of drugs often involves complex chemical reactions to create the desired compounds, or the extraction of active ingredients from raw materials. Synthetic production can include a wide array of chemical engineering techniques, while extraction usually involves isolating specific compounds from plants or other natural sources.

Recycling materials generally does not pertain to the process of creating drugs, as it focuses on reprocessing used materials for new uses rather than the chemical manipulation needed to produce substances. Online marketing and exporting goods also do not inherently involve the manufacture of controlled substances; they relate more to the distribution of products rather than their creation.