Who served the royalty in the palaces? People often say the Hakka did. 

A People often say the Hakka were those who served the royalty in the palaces.

B It is often said who served the royalty were the Hakka in the palaces.

C People often say that the Hakka knew who served the royalty in the palaces.

D The Hakka often said to those who served the royalty in the palaces.