Background:
During the early 20th century, India was one of the largest exporters of yarn to China. However, the export of Indian yarn to China started declining from a certain point in time. Let's explore when this decline occurred.

Evidence:
The decline in the export of Indian yarn to China can be attributed to various factors. However, the specific time period when this decline began can be traced back to historical records.

Explanation:
The correct answer is option 'A' - 1906.

1. 1906: This year marks the beginning of the decline in Indian yarn exports to China. It was during this time that the export of Indian yarn to China started to decrease significantly.

2. Reasons for the decline: Several factors contributed to the decline in Indian yarn exports to China during this period:

- Competition from Japan: Japan emerged as a strong competitor in the textile industry during the early 20th century. Japanese textiles gained popularity in China, leading to a decrease in demand for Indian yarn.

- Political unrest in China: China was going through a period of political unrest and turmoil during this time. The instability in the country affected its economy and trade relations with other nations, including India.

- Development of local Chinese textile industry: China started developing its own textile industry, leading to a shift in preference towards domestic production. The growth of the Chinese textile industry further reduced the demand for Indian yarn.

3. Impact: The decline in Indian yarn exports to China had significant repercussions for the Indian textile industry. It led to a decrease in revenue and profits for Indian textile manufacturers and exporters.

4. Shift in trade patterns: As the export of Indian yarn to China declined, India had to explore new markets and diversify its textile exports. This shift in trade patterns had long-term implications for the Indian textile industry.

In conclusion, the export of Indian yarn to China declined starting from 1906. This decline was influenced by factors such as competition from Japan, political unrest in China, and the development of the local Chinese textile industry. The decline had a significant impact on the Indian textile industry, leading to a shift in trade patterns and the exploration of new markets.