According to ancient records, natural magnets were employed in China as direction-finding devices. This led to the first compass, called （）during the Warring States Period.

According to ancient records, natural magnets were employed in China as direction-finding devices. This led to the first compass, called （）during the Warring States Period.
A.wet compass
B.Si Nan
C.dry compass
D.navy compass
正确答案：Si Nan