Which statement about the Sui Dynasty is correct?

It lasted for more than five hundred years until it was conquered by the forces of Attila the Hun.

It was the last Chinese dynasty to have its imperial capital located at the northern city of Chang'an.

It's first ruler was Wendi, who unified northern China and seized control of western regions.

It dismantled large portions of the Great Wall to obtain building materials for a network of canals.

It is correct that the first Sui ruler was Wendi, who unified northern China and seized control of western regions.

Explanation:

The Sui Dynasty was a Chinese dynasty founded in 581 in northern China by Yang Jian, a former servant, who renamed himself as Emperor Wendi. In 589, his troops occupied southern China, ending the reign of the last southern Chen Dynasty and thus reuniting China after a quarter-century of disunity. In an effort to consolidate his achievement, Emperor Wendi, as well as his son and successor, Emperor Yang, undertook a series of far-reaching reforms, primarily aimed at standardizing money, reducing social differences among subjects, rebuilding the Great Wall, creating a new administrative system, promoting Buddhism, and what is often considered to be the most important, the completion of the Grand Canal, which first created the North and South China transport links, thus enabling the renewal of cultural ties and nationhood in the following centuries.