The correct answer is, it is true that Shihuangdi said that one type of money or currency would be used throughout China.
He was the first emperor of China. He is recognized for being an rigid and firm ruler that had excellent organization to govern his vast empire. He split the country in 36 parts and ordered the same number of officials to administer those regions.
For administrative purposes and better trading, when he unified China he also made the Banliang coin of the Qin state the official currency of the empire. All of the other types of money were obsolete.