Which of the Following Reflects a Way That the Persians

Which of the following reflects a way that the Persians integrated their multiethnic empire?

A) Persian administrators taught Old Persian to the local populations in order to create a common language for governmental affairs.
B) Local provinces were allowed to keep their own currency and standards of weights and measures in order to promote trade.
C) All subject peoples' beliefs and customs were respected and they were required only to give loyalty and pay tribute to the king.
D) All subject peoples were required to convert to Zoroastrianism,in order to create a common religion throughout the kingdom.