Correct
开元
/ kāiyuán /
Strokes
Definition
Tang emperor Xuanzong's 唐玄宗[táng xuán zōng] reign name used during the Kaiyuan era (713-741), a peak of Tang prosperity
Example
As a Noun
Kaiyuan ［title of the 713-741 reign of Li Longji（李隆基）(685-762) of the Tang Dynasty (608-907)］