Answer: B. Improving Agricultural techniques with Irrigation and fast rising rice increased food supplies.
Step-by-step explanation:
The Song Dynasty of China which lasted from 960 - 1279 AD saw a great increase in population as well as income. This was due to improvements in Agriculture that led to increased food supplies which could support a larger population.
Some of these improvements included irrigation as more farming commenced on the Yangzi River which increased crop yields as well as the introduction of different types of rice such as fast rising rice which meant that more rice could be grown in planting season.