Answer:
B. geographic features protected the North China Plain.
Explanation:
The North China Plain is protected on four fronts by imposing geographical feature, which allowed early Chinese civilization to flourish without much external influence or threat.
To the north, the Gobi Desert, to the West, the Chinese Mountains, and the Tibet, to the South, more mountains, and to the West, the China Sea and the Pacific Ocean.
Is not really a responsibility because it is not a requirement just something you can do that could help
The crusades sent to spread Christianity