The answer is b
Yada yada yada
By completing with other nations and expanding boundaries
In 1976, the United States of America celebrated it's Bicentennial. Good luck on your homework.
Answer:
Heavy taxation and compulsory labor duties caused widespread revolts and a brief civil war. ... After capturing Daxing (now Xi'an), Li Yuan declared himself Emperor Gaozu of the Tang Dynasty in the year 618.
Explanation:
Hope this helps :D