Final answer:
The tree-bark paper was not invented during the Han dynasty.
Step-by-step explanation:
The correct answer is d. tree-bark paper. During the Han dynasty, several important inventions were made, including writing, a Chinese dictionary, and acupuncture. However, tree-bark paper was not invented during that time. Tree-bark paper was actually developed around 105 AD during the Eastern Han dynasty. It was made by boiling the inner bark of trees such as mulberry, hemp, and bamboo, and then pounding it into a pulp to create paper.
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