一道语法题（主要是想搞清楚一个知识点）

39. GWD30-Q39:

In addition to being China’s first administrators, in the sense that they developed a coherent bureaucracy for their empire, the first literate culture in East Asia were the Shang, and they were well known for crafting ornate bronze ritual vessels.

1. the first literate culture in East Asia were the Shang, and they were well known for crafting
2. the first literate culture in East Asia were the Shang, well known as the crafters of
3. the Shang, as the first literate culture in East Asia, is well known for its crafting
4. the Shang were the first literate culture in East Asia and are well known as the crafters of
5. the Shang were the first literate culture in East Asia and well known for its crafted

答案选D，我不明白的主要就是the Shang的谓语为什么用复数？请大牛指教。